THE  LIBRARY 

OF 
SANTA  BARBARA 

COLLEGE  OF 

THE  UNIVERSITY 

OF  CALIFORNIA 


PRESENTED  BY 

MRS.  T.  MITCHELL  HASTINGS 
IN  MEMORY  OF 


T.  MITCHELL  HASTINGS 


1 IETCHLLL  HASTJN8& 


6*7- 


EXTRACT  FROM  TABLE  OF  CONTENTS. 

PART  II. 


CHAPTER  I. 

The  Building  and  Finishing  Woods  of  the  United  States.— Their  char- 
acteristics, properties  and  uses. 

CHAPTER  II. 

Wood  Framing — Ordinary  Construction. — Framing  timber — Framing  of 
wooden  buildings — Framing  of  floors,  supports  for  partitions,  roof  construc- 
tion— Superintendence. 

CHAPTER  III. 

Sheathing,  Windows  and  Outside  Door  Frames.— Sheathing  of  walls  and 
roof — Cellar  frames — Types  of  windows,  construction  of  window  frames  in 
frame  and  brick  walls,  patent  windows,  casement  windows,  pivoted  windows, 
bay  windows — Sash,  store  fronts — Glass  and  glazing — Outside  door  frames. 

CHAPTER  IV. 

Outside  Finish,  Gutters,  Shingle  Roofs. — Eaves  and  gable  finish,  gutters  and 
conductors  —  Siding  —  Porches  —  Dormers — Shingling,  flashing — Wood  sky- 
lights. 

CHAPTER  V. 

Furring,  Inside  Finish,  Doors,  Stairs. — Furring  for  finish  and  plastering — 
Grounds  and  corner  beads — Flooring — Doors  and  door  frames — Casing  of 
doors  and  windows — Paneling,  beams,  columns,  stairs. 

CHAPTER  VI. 

Builders'  Hardware, — Heavy  hardware,  bolts,  nails,  screws — Finishing  hard- 
ware, butts,  locks,  knobs,  bolts,  window  trimmings,  trimmings  for  blinds  and 
shutters 

CHAPTER  VII. 

Heavy  Framing. — Framing  of  posts  and  girders,  bracing,  mill  floors — Compound 
and  trussed  girders — Suspended  floors,  galleries. 

CHAPTER  VIII. 

Specifications. — Carpenters'  work — Joiners'  Work — Hardware. 
APPENDIX. 

Tables  of  Strength  of  wood  and  cast  iron  columns,  wooden  beams,  maximum  span 
for  floor  joists. 


I.  MITCHELL  HASTINGS. 

BUILDING  CONSTRUCTION 

AND  SUPERINTENDENCE. 


BY  F.  E.  KIDDER,  C.  E.,  PH.  D., 

ARCHITECT. 

Fellow  American  Institute  of  Architects. 
Author  of  "  The  Architects'  and  Builders'  Pocket  Book.n 


PART  I. 
THIRD  EDITION. 

MASONS'    WORK, 

260  Illustrations. 


New  York : 

WILLIAM  T.  COMSTOCK, 

23  Warren  Street. 

1808. 


COPYRIGHT, 

F.  E.  KIDDER. 

1896. 

COPYRIGHT, 
F..E.  KIDDER. 

1897. 

COPYRIGHT, 
F.  E.  KIDDER. 

4898. 


PREFACE 


THE  primary  object  of  the  Author  in  preparing  this  volume  has  been  to  present 
to  the  Student,  Architect  and  Builder  a  text  book  and  guide  to  the  materials 
used  in  Architectural  Masonry  and  the  most  approved  methods  of  doing  the  various 
kinds  of  work,  and  incidentally  to  point  out  some  of  the  ways  in  which  such  work 
should  not  be  done,  and  the  too  frequent  methods  of  slighting  the  work.  That 
there  is  a  demand  for  such  a  work  has  been  evidenced  to  the  Author  by  numerous 
inquiries  from  Architects  and  instructors  in  our  Architectural  schools,  and  also  by 
the  fact  that  there  exists  no  similiar  work  describing  American  methods  and 
materials. 

In  describing  methods  of  construction  the  Author  has  drawn  largely  from  his  own 
observation  and  experience  as  a  practicing  and  consulting  Architect  in  both  the 
Eastern  and  Western  States,  although  much  assistance  has  been  obtained  from 
prominent  Architects,  who  have  .cheerfully  aided  him  by  their  advice  and  experience, 
and  from  the  various  books  and  publications  to  which  references  are  made  in  the 
text ;  to  all  such  the  author  gratefully  acknowledges  his  indebtedness. 

To  make  the  book  convenient  for  practical  use  and  ready  reference,  the  various 
subjects  have  been  paragraphed  and  numbered  in  bold-face  type,  and  numerous  cross 
references  are  made  throughout  the  book.  The  table  of  contents  shows  the  general 
scope  of  the  book,  the  running  title  assisting  in  finding  the  various  parts,  and  a  very 
full  index  makes  everything  in  the  book  easy  of  access.  The  general  character  of 
the  work  is  descriptive,  and  hence  rules  and  formulae  for  strength  and  stability  have, 
except  in  a  few  cases,  been  omitted  ;  such  data  being  already  fully  presented  in  the 
Author's  ' '  Pocket  Book  "  and  other  similar  works. 

While  intended  principally  as  a  book  of  instruction,  there  is  much  in  the  book 
that  will  be  found  valuable  for  reference,  and  of  assistance  in  designing  and  laying 
out  mason  work,  preparing  the  specifications,  and  in  superintending  the  construction 
of  the  building,  so  that  the  Author  hopes  that  even  the  experienced  Architect  will 
find  it  of  assistance  in  his  work. 

The  enterprising  builder,  also,  who  wishes  to  thoroughly  understand  the  mate- 
rials with  which  he  has  to  deal,  and  the  way  in  which  they  should  be  used,  will 
find  in  this  book  much  information  that  cannot  be  readily  obtained  elsewhere. 

To  make  the  description  as  clear  as  possible  many  illustrations  (mostly  from  orig- 
inal drawings)  have  been  inserted,  and  an  endeavor  has  been  made  to  present  only 
practical  methods,  and  to  favor  only  such  materials  as  have  been  found  suitable  for 
the  purpose  for  which  they  are  recommended. 

F.  E.  KIDDER. 

Denver,  Cola  ,June  i,  i&fi. 


TABLE  OF  CONTENTS. 


Introduction 9 

Requirements  for  the  Successful  Practice  of  Architecture — Superintend- 
ence of  Building  Construction. 

CHAPTER  I. 

Foundations  on  Firm  Soils 13 

Staking  Out  the  Building.  Foundations — light  buildings — nature  of 
soils,  bearing  power  of  soils,  examples  of  actual  loads,  methods  of  testing. 
Designing  the  Foundations,  proportioning  the  footings,  examples,  centre 
of  pressure  to  coincide  with  centre  of  base.  Superintendence. 

CHAPTER  II. 

Foundations  on  Compressible  Soils 31 

Pile  Foundations — classes  of  piles,  material,  pointing  and  ringing,  man- 
ner of  driving,  bearing  power,  actual  loads  on  piles,  cutting  off  and  cap- 
ping. Grillage.  Spread  Foundations — concrete  with  tension  bars— 
steel  beam  footings,  method  of  calculating.  Timber  Footings,  calcula- 
tions for — foundations  for  temporary  buildings.  Masonry  Wells,  examples 
of.  Caissons,  examples  of. 

CHAPTER  III. 

Masonry    Footings    and    Foundation    Walls — Shoring   and    Under- 
pinning      6a 

Masonry  Footings — concrete  footings,  stone  footings,  offsets,  brick  foot- 
ings. Inverted  Arches,  calculations  for.  Foundation  Walls — bonding,  fill- 
ing of  voids,  thickness  of  walls.  Retaining  Walls,  proportions — Area 
Walls— Vault  Walls— Filling  in.  Dampness  in  Cellar  Walls.  Window 
and  Entrance  Areas — Pavements.  Cement  Walks.  Shoring — Needling — 
Underpinning — Bracing. 

CHAPTER  IV. 

Limes,  Cements  and  Mortars 93 

Lime — characteristics  of,  slaking  and  mixing.  Sand.  White  and  Colored 
Mortars.  Durability  of  Lime  Mortar.  Hydraulic  Lime — Pozzuolanas. 
Natural  Cements — distribution  of,  analysis  of,  characteristics,  testing — 
Roman  Cement.  Portland  Cement — American  Cement — testing,  strength, 
specifications  for.  Cement  Mortars — use,  mixing,  proportions — Grout. 
Data  for  Estimating  Cost  of  Mortar.  Strength  of  Mortar.  Freezing  of 
Mortar.  Concrete — mixing,  proportions,  depositing,  data  for  estimating. 
Mortar  Colors  and  Stains— mixing. 


6  TABLE  OF  CONTENTS. 

CHAPTER  V. 
Building  Stones 124 

Granites — characteristics  of,  distribution  of.  Limestone — characteristics  of, 
description  of  principal  varieties.  Marble — Description  of  American  Mar- 
bles— Onyx  Marbles.  Sandstones — characteristics  of,  description  of  well- 
known  varieties.  Lava  Stone.  Slate — qualities  and  distribution  of. 
Selection  of  Building  Stones — method  of  finishing,  strength.  Testing  of 
Building  Stones — Seasoning  of  Stone — Protection  and  Preservation  of 
Stonework. 

CHAPTER  VI. 

Cut   Stonework 150 

Rubble  Work — Ashlar.  Stonecutting  and  Finishing— tools,  kinds  of  fin- 
ish. Laying  Out — trimmings,  relieving  and  supporting  lintels,  sills,  arches, 
label  mouldings,  relieving  beams  over  arches,  elliptical  arches,  flat  arches, 
rubble  arches — Centres.  Miscellaneous  trimmings — columns,  copings, 
stone  steps  and  stairs.  Slip  Joints.  Bond  Stones  and  Templates.  Set- 
ting Stonework — protecting,  pointing,  cleaning  down.  Strength  of  Stone 
Masonry — lintels,  columns.  Measurement  of  Stonework.  Superintendence 
of  Cut  Stonework. 

CHAPTER  VII. 

Brickwork 189 

Bricks — composition,  manufacture,  glazed  and  enameled,  paving,  fire 
bricks.  Classes  of  Building  Brick — common  brick,  pressed  brick.  Color 
of  bricks,  size  and  weight.  Requisites  of  good  brick — strength.  Brick- 
work— thickness  of  mortar  joints,  laying  brick,  wetting  brick,  laying  in 
freezing  weather.  Ornamental  Brickwork — belt  courses,  cornices,  surface 
patterns.  Construction  of  Walls — bond,  anchoring  the  wall,  corbeling  for 
floor  joist,  bonding  at  angles,  openings,  joining  new  walls  to  old.  Thick- 
ness of  Walls — party  walls.  Wood  in  Walls — cracks  in  walls.  Damp- 
proof  Courses.  Hollow  Walls — methods  of  construction,  bonding.  Brick 
Veneer  Construction.  Details — brick  arches,  vaults,  chimneys,  fireplaces, 
brick  nogging.  Cleaning  Down — efflorescence — damp-proofing.  Crushing 
Strength  of  Brickwork.  Measurement  of  Brickwork.  Superintendence. 

CHAPTER  VIII. 
Architectural  Terra  Cotta 249 

Composition  and  manufacture,  color,  use,  durability,  inspection.  Laying 
Out.  Examples  of  Construction.  Setting  and  Pointing — cost,  weight  and 
strength,  protection. 

CHAPTER  IX. 

Fireproofing 258 

Materials — dense  tiling,  porous  tiling,  concretes.  Floor  Construction — 
side-method  arches,  end-method  arches,  combination  of  side  and  end 
methods.  Depth,  Weight  and  Strength  of  Flat  Tile  Arches — manner  of 
setting — protection.  Floor  and  Ceiling  Finish.  Segmental  Tile  Arches. 
Guastavino  Arch.  The  "Fawcett"  Floor.  Concrete  and  Metal  Floors — 
the  Ransome  &  Smith  floor — the  Lee  tension  member  floor — the  Metropol- 
itan floor — the  Roebling  floor— the  Columbian  floor.  Actual  Weight  of 
Fireproof  Floors  ;  selection  of  a  system.  Fireproof  Roofs-  flat  roofs,  pitch, 


TABLE  OF  CONTENTS.  7 

and  mansard  roofs.  Ceilings.  Girder  and  Column  Casings.  Partitions — 
thin  partitions.  Wall  Furring. 

CHAPTER  X. 

Iron  and  Steel  Supports  for  Mason  Work. — Skeleton  Construction.  301 

Girders  and  Lintels — cast  iron  lintels,  cast  iron  arch  girders.  Supports  for 
Bay  Windows.  Wall  Supports  in  Skeleton  Construction-^spandrel  sup- 
ports, bay  window  supports.  Miscellaneous  Ironwork — bearing  plates, 
skewbacks,  shutter  eyes,  door  guards,  chimney  caps,  ladders,  coal  hole 
covers. 

CHAPTER  XI. 

Lathing  and  Plastering 318 

Lathing — wood  lathing,  metal  lathing,  wire  lath,  furring  for  wire  lath, 
stiffened  wire  lath — expanded  metal  and  perforated  laths.  Plaster  Boards. 
Where  Metal  Lathing  should  be  Used.  Plastering — materials  for,  mixing, 
machine-made  mortar — proportions  of  materials — Putting  On  the  Plaster. 
Hard  Wall  Plasters — nature  of,  advantages,  how  used  and  sold.  Stucco 
Work — Keene's  cement,  scagliola,  fibrous  plaster.  External  Plastering — 
stucco,  staff.  Whitewashing.  Lath  and  Plaster  in  Fireproof  Construction — 
thin  partitions.  Plastering  Superintendence.  Measuring  Plasterers'  Work. 
Cost. 

CHAPTER  XII. 

Concrete  Building  Construction 357 

Use  of  Concrete  for  Buildings.  Examples  of  Notable  Concrete  Buildings 
in  the  United  States.  Details  of  Construction — surface  finish,  making  the 
concrete,  expansion  and  contraction.  Fireproof  Vaults.  Sidewalk  Con- 
struction. 

CHAPTER  XIII. 

Specifications 370 

Introduction.  General  Conditions.  Excavating  and  Grading.  Piling. 
Concrete  Footings.  Stonework — footings,  foundatipn  walls,  external 
stone  walls,  cut  stonework.  Brickwork.  Laying  Masonry  in  Freezing 
Weather.  Fireproofing — hollow  tile  system.  Architectural  Terra  Cotta. 
Lathing  and  Plastering — ordinary  work,  hard  wall  plasters,  wire*  lathing 
and  furring,  thin  partitions. 

Appendix 391 

Table  A.  Weight,  Crushing  Strength  and  Ratio  of  Absorption  of  Build- 
ing Stones. 

Table  B.  Chemical  Composition  of  Building  Stones. 
Table  C.   List  of  Prominent  Stone  Buildings. 
Table  D.  Effect  of  Heat  on  Various  Stones. 
Table  E.  Actual  Crushing  Strength  of  Brick  Piers. 
Table  F.  Safe  Working  Loads  for  Masonry. 
Table  G.   Properties  of  Timber,  Stones,  Iron  and  Steel 
Making  Cellars  Wa'.erproof. 

[OVER] 


8  TABLE   OF   CONTENTS. 

ADDITIONS  TO    SECOND    EDITION. 

Brick  Fireplaces 242* 

Brick  Spiral  Stairs 242* 

Expanded  Metal  Furring  in  Fireproof  Buildings 35O« 

Door  and  Window  Frames  in  Thin  Fireproof  Partitions 351 

Colored  Sand  Finish 356 

Other  Uses  for  Concrete  Construction 369 

Stain  and  Damp-proofing — Antihydrine 403 

Roebling  Fireproof  Floor,  Weight  and  Strength 404 

Expanded  Metal  Systems  of  Floor  Construction 406 

Terra  Blanca  Fireproof  Tiling 408 

Pelton's  System  of  Released  Ashlar 410 


INTRODUCTION. 


THE  successful  practice  of  Architecture  requires  not  only  ability  to  draw  and 
design,  but  also  a  thorough  knowledge  of  building  construction  in  all  its 
branches,  at  least  so  far  as  to  know  how  the  work  should  be  done,  and 
conscientious  and  painstaking  supervision  of  the  work. 

Without  a  knowledge  of  the  best  methods  of  performing  building  operations, 
and  of  the  materials  that  should  be  used,  it  is  impossible  for  the  architect  to  pre- 
pare his  specifications  intelligently,  and  so  as  to  secure  the  kind  of  work  he  wishes 
done  ;  and  upon  the  thoroughness  with  which  the  specifications  are  prepared 
depends  in  a  great  measure  the  satisfactory  execution  of  the  work. 

The  position  occupied  by  the  architect  as  a  judge  or  referee  between  the 
owner  and  contractor  also  makes  it  necessary  that  he  should  be  able  to  show  such 
thorough  familiarity  with  common  practice  as  will  command  the  respect  of  both. 
Workmen  soon  discover  whether  the  superintendent  is  familiar  with  the  difference 
between  good  and  bad  work,  and  if  they  find  him  wanting  they  are  quite  sure  to 
take  advantage  of  his  lack  of  knowledge. 

After  the  plans  and  specifications  have  been  prepared  with  the  utmost  care, 
accidents,  failures  and  bad  work  are  quite  sure  to  occur  unless  the  building  opera- 
tions are  carefully  and  intelligently  supervised.  In  fact,  probably  more  failures  in 
buildings  occur  from  the  use  of  poor  materials  and  bad  workmanship  than  from 
faults  in  the  plans. 

While  it  is  impossible  for  one  to  acquire  a  thorough  knowledge  of  building 
construction  from  books  alone,  it  is  necessary,  for  the  young  architect,  especially, 
to  depend  upon  technical  books  to  a  large  extent  for  his  knowledge  of  how  work 
should  be  done,  and  of  what  materials  are  best  suited  for  certain  purposes,  and 
how  they  should  be  used.  As  a  substitute  for  his  lack  of  knowledge,  he  must  rely 
largely  upon  knowledge  gained  through  the  experience  of  others,  oftentimes  at 
great  cost. 

In  these  books  the  author  has  endeavored  to  describe  all  the  ordinary  building 
operations  in  such  a  way  that  they  may  be  easily  understood,  and  to  point  out  the 
defects  often  met  with  in  building  materials  and  construction,  and  to  indicate  in  a 
measure  how  they  may  be  avoided. 

To  get  along  well  with  contractors  and  workmen  the  architect  must  feel  sure 
that  his  opinions  and  decisions  are  correct,  and  stick  to  them.  Of  course  one  can 
often  learn  much  from  practical  builders,  but  unless  he  is  already  somewhat 
informed  upon  the  subject  he  is  often  likely  to  be  imposed  upon.  In  fact,  one  of 
the  greatest  troubles  of  young  architects  in  superintending  their  buildings,  lies  in 


io  INTRODUCTION. 

the  persistence  with  which  builders  and  workmen  will  insist,  often  to  the  owner, 
that  such  and  such  methods  or  materials  are  the  best  for  the  purpose,  or  that  the 
work  should  be  done  in  such  and  such  a  way,  or  that  this  or  that  requirement  is 
unnecessary  and  not  called  for  by  older  architects.  Oftentimes  these  assertions 
are  deliberate  misrepresentations,  made  to  save  expense  or  labor,  and  unless  the 
architect  is  well  posted  on  the  subject,  and  can  quote  good  authorities  for  his 
views,  it  is  difficult  to  combat  them. 

"The  best  workmen  dislike  to  pull  down  or  change  what  is  already  done,  and 
if  inadvertence  or  temporary  convenience  has  led  them  into  palpable  violation  of 
the  specifications,  they  will  often  stretch  the  truth  considerably  in  their  explana- 
tion ar.d  excuse." 

In  pursuing  his  examinations  of  the  work  it  is  important  that  the  architect  or 
superintendent  shall  have  a  systematic  plan,  that  all  the  innumerable  points  of 
construction  shall  receive  attention  at  the  proper  time,  and  before  they  are  covered 
up  or  built  over  so  as  to  make  changes  inconvenient  or  impossible.  If  the  super- 
intendent is  not  also  the  architect,  he  should,  before  the  work  is  commenced,  care- 
fully study  the  plans  and  specifications  and  make  himself  thoroughly  familiar  with 
all  the  points  of  construction,  so  that  no  important  feature  will  be  overlooked.  He 
should  carefully  examine  and  verify  all  figures,  to  see  that  no  mistakes  have  been 
made  before  the  work  progresses  too  far. 

In  making  periodical  visits  to  the  building  he  should  go  all  over  the  building 
and  examine  closely  all  work  that  has  been  done  since  his  last  visit.  Wherever  a 
man  has  been  at  work  he  should  go  and  see  what  has  been  done.  It  is  only  in  this 
way  that  the  superintendent  can  insure  against  concealed  defects  or  poor  materials. 
"When  he  is  superintending  several  buildings  at  the  same  time,  he  should  read  the 
specifications  and  examine  the  plans  frequently,  to  refresh  his  memory,  otherwise 
he  may  overlook  some  featwres  that  cannot  be  as  well  attended  to  afterward. 

Another  important  point  in  efficient  supervision  is,  after  inspecting  the  mate- 
rials delivered,  to  make  sure  that  those  rejected  are  removed  from  the  building, 
and  not  used  during  his  absence.  All  defective  materials  should  be  marked  in 
some  way,  on  their  face,  so  that  they  cannot  be  used  without  the  mark  showing, 
should  the  material  be  incorporated  in  the  building.  The  superintendent  should 
also  insist  that  work  which  has  been  improperly  done  shall  be  taken  down  at 
once,  and,  if  necessary,  take  it  down  or  remove  it  himself.  Any  mistakes  or  bad 
work  that  are  discovered  should  also  be  pointed  out  or  condemned  at  the  time, 
before  they  are  driven  out  of  the  mind  by  other  matters. 

It  is  very  essential  that  the  superintendent  shall,  at  the  start,  insist  on  having 
the  work  done  as  specified,  and  be  very  careful  to  reject  all  unfit  material,  for  if  the 
contractor  finds  him  lenient  at  the  start  he  will  be  sure  to  take  advantage  of  it,  and 
slight  the  work  more  and  more.  If,  on  the  other  hand,  he  finds  that  the  work 
must  be  done  right,  or  else  rebuilt,  he  will  be  careful  to  do  the  work  in  such  a  way 
that  it  will  not  have  to  be  done  over  again.  A  great  fault  with  many  superintend- 
ents is  that  they  do  not  feel  sufficient  confidence  in  their  own  judgment  and  have 
not  the  courage  to  insist  on  their  directions  being  followed. 

In  describing  the  different  building  operations  the  author  has  endeavored  to 
call  attention  to  the  points  that  particularly  need  to  be  inspected,  and  to  some  of 
the  ways  in  which  defective  materials  or  construction  are  covered  up.  There  are, 
the  author  is  glad  to  say,  many  honest  builders,  who  do  not  countenance  bad  work- 


IN  TROD  UCTION.  1 1 

manship,  but  the  temptation  to  save  money,  especially  when  the  work  is  taken  at  a 
low  figure,  is  so  great  that  the  architect  should  consider  that  his  duty  to  his  client 
and  to  himself  is  not  fulfilled  until  he  has  satisfied  himself  by  careful  inspection 
that  the  work  is  being  done  in  the  manner  specified.  Even  when  the  contractor 
does  not  wish  to  slight  the  work,  there  are,  unfortunately,  many  workmen  who 
seem  to  prefer  to  do  a  poor  job  rather  than  a  good  one,  and  who,  rather  than 
lift  a  heavy  stone,  will  break  it  in  two,  or  save  themselves  all  the  labor  possible, 
so  long  as  their  work  will  pass  unnoticed. 

For  such,  the  only  treatment  is  to  require  a  strict  observance  of  the  specifica- 
tions and  the  superintendent's  directions,  with  the  certain  penalty  for  violation  of 
having  to  do  their  work  over  again. 


CHAPTER  I. 
FOUNDATIONS  ON  FIRM  SOILS. 


STAKING  OUT  THE  BUILDING. 

I.  Except  for  city  blocks,  staking  out  the  building  is  gen- 
erally left  to  the  contractor,  but  the  superintendent  should  see 
that  it  is  carefully  done,  and  very  often  he  is  expected  or  called 
upon  to  assist  in  running  the  lines.  The  principal  corners  of 
the  building  should  first  be  carefully  located  by  small  stakes  driven; 
into  the  ground  with  a  nail  or  tack  marking  the  exact  intersec- 
tion of  the  lines.  The  lines  should  then  be  marked  on  batter 
boards,  put  up  as  shown  in  Fig.  i.  Three  large  stakes  (2x4  or  4x4) 

are  firmly  driven  or  set 
in  the  ground  at  each  cor- 
ner of  the  building  and 
from  six  to  ten  feet  from 
the  line  of  the  building, 
according  to  the  nature 
of  the  ground,  and  fence: 
boards  nailed  horizon- 
tally from  the  corner  post 
to  each  of  the  other  two^ 
posts.  These  boards 
should  be  long  enough 
so  that  both  the  inside 
and  outside  lines  of  the 
foundation  walls  may  be 
marked  on  them.  The 
stakes  should  also  be 
braced  from  the  bottom 
of  the  corner  stake  to  the 
top  of  the  others.  This 
makes  a  firm  support  for 
the  lines  and  one  that  need  not  be  moved  until  the  walls  are  up  for 
the  first  floor.  These  boards  have  the  great  advantage  over  single 
stakes  that  they  are  more  permanent,  and  that  all  projections  of  the 
walls,  such  as  footings,  basement  wall  and  first  story  wall,  can  readily 


i4  BUILDING  CONSTRUCTION. 

be  marked  on  them.  It  is  a  good  idea  to  indicate  the  ashlar  line  by 
a  saw  mark,  the  basement  line  by  a  nail  and  the  footings  by  a  notch, 
then  no  mistake  can  be  made  by  the  workmen.  If  the  top  of  all  the 
horizontal  boards  are  kept  on  a  level  it  assists  a  great  deal  in  getting 
levels  for  the  excavating,  etc. 

The  superintendent  will  be  expected  to  furnish  the  contractor  with 
a  bench  mark,  from  which  he  can  get  the  level  for  his  footings,  floor 
joist,  etc.  This  mark  should  be  put  on  some  permanent  object, 
where  it  can  be  referred  to  after  the  first  floor  joists  are  on.  In  giving 
such  data  to  the  contractor  the  superintendent  must  be  very  careful, 
as  he  can  be  held  responsible  for  any  loss  resulting  from  errors  which 
he  may  make.  It  is  a  very  safe  and  good  rule  to  give  as  few  lines, 
data  or  measurements  as  possible  to  contractors,  requiring  them  to 
lay  out  all  the  work  themselves  and  to  be  alone  responsible  for  the 
accuracy  of  their  work. 

2.  Diagonals. — After  the  batter  boards  are  in  place  and  properly 
marked,  the  superintendent  should  require  the  contractor  or  his  fore- 
man to  stretch  the  main  lines  of  the  building,  and  the  superintendent 
should  carefully  measure  the  diagonals,  as  A  B  and  C  D,  Fig  i,  with 
a  steel  tape  ;  if  they  are  not  exactly  of  the  same  length  the  lines  are 
not  at  right  angles  with  each  other  and  should  be  squared  until  the 
diagonals  are  of  equal  length. 

On  fairly  level  ground  a  building  may  be  accurately  laid  out  by 
means  of  a  steel  tape,  using  multiples  of  3,  4  and  5  for  the  sides  and 
hypothenuse  of  a  right  angle  triangle.  The  larger  the  triangle  the 
more  accurate  will  be  the  work. 

3.  For  buildings  which  are  built  out  to  the  street  line  the  lines  of 
the  lot  should  be  given  by  a  surveyor  employed  by  the  owner,  and 
should  be  fixed  by  long  iron  pins  driven  into  the  street,  or  by  lines 
cut  on  the  curbstone  across    the    street.     In  building  close  to  the 
party  lines  of  a  lot  it  is,  of  course,  of  great  importance  that  the  build- 
ing does  not  encroach  upon  the  adjacent  lot,  and  to  prevent  this  it  is' 
always  well  to  set  back  one  inch  from  the  line,  thus  allowing  for  any 
irregularities  or  projections  in  the  wall. 

FOUNDATIONS— LIGHT  BUILDINGS. 

4.  Nature  of  Soils. — The  architect  should  in  all  cases  make 
every  endeavor  to  discover  the  nature  of  the  soil  upon  which  his 
building  is  to  be  built  before  he  makes  his  foundation  plan.     For 
most  buildings,  a  sufficient  idea  of  the  nature  of  the  soil  may  be 
gained  by  inquiry  amongst  builders  who  have  put  up  buildings  on  the 


FOUNDATIONS  ON  FIRM  SOILS.  15 

adjacent  lots.  Many  soils,  however,  vary  greatly,  even  in  a  distance 
of  100  feet,  owing  to  the  strata  having  a  decided  dip,  and  on  all  such 
soils  much  trouble  and  annoyance  may  often  be  saved  by  having  bor- 
ings made  with  a  post  auger,  showing  the  composition  of  the  soil  at 
different  strata.  If  two  borings  made  on  different  sides  of  the  site 
show  about  the  same  depth  and  character  of  soil  it  may  be  assumed 
that  other  borings  would  give  the  same  result,  but  if  the  soil  brought 
up  by  the  first  two  borings  show  a  difference  in  the  character  of  the 
soil,  or  indicate  that  the  strata  have  a  decided  pitch,  then  borings 
should  be  made  all  around  the  foundations. 

For  ordinary  buildings  borings  to  the  depth  of  8  or  10  feet  are 
generally  sufficient,  although  a  6  or  8-inch  auger  may  be  driven  to 
the  depth  of  20  or  25  feet  by  two  men  using  a  lever.  In  soft  soils  a 
pipe  must  first  be  sunk  and  the  auger  worked  inside  of  it.  A  smaller 
auger  will  answer  in  such  cases. 

For  dwellings  built  on  sand,  gravel,  clay  or  rock,  an  examination 
of  the  bottom  of  the  trenches,  and  a  few  tests  with  an  ordinary  crow- 
bar or  post  auger,  will  generally  be  all  that  is  necessary. 

When  borings  are  deemed  necessary  the  owner  should  be  advised 
of  the  fact,  and  his  authority  obtained  for  incurring  the  expense, 
which  should  be  defrayed  by  him. 

5.  Different  soils  have  not  only  different  bearing  or  sustaining 
powers,  but  also  various  peculiarities  which  must  be  thoroughly  un- 
derstood and  considered  when  designing  the  foundation. 

An  architect  who,  as  a  draughtsman,  has  had  several  years'  expe- 
rience in  one  locality  before  practicing  for  himself,  will  naturally 
have  become  acquainted  with  the  peculiarities  of  the  soil  in  that 
vicinity  ;  but  should  his  practice  extend  beyond  his  own  city  he 
should  carefully  study  the  nature  and  peculiarities  of  the  soil  in  each 
different  locality  where  he  may  have  work,  and  also  obtain  all  the 
information  possible,  bearing  on  the  subject,  from  local  builders,  as 
otherwise  he  may  fall  into  serious  trouble. 

No  part  of  a  building  is  more  important  than  the  foundation,  and 
more  cracks  and  failures  in  buildings  will  be  found  to  result  from 
defective  foundations  than  from  any  other  cause  ;  and  for  any  such 
defects,  resulting  from  the  neglect  of  usual  or  necessary  precautions, 
the  architect  is  responsible  to  the  owner,  besides  the  damage  which 
inevitably  results  to  his  own  reputation. 

The  following  observations  are  intended  as  a  general  guide  in  pre- 
paring foundations  on  different  soils,  although  they  should  be  sup- 
plemented by  the  experience  of  local  builders  wherever  possible. 


16  BUILDING  CONSTRUCTION. 

6.  Rock. — Rock,  when  it  extends  under  the  entire  site  of  the 
building,  makes  one  of  the  best  foundation  beds,  as  even  the  softest 
rocks  will  safely  carry  more  weight  than  is  likely  to  come  upon  them. 

The  principal  trouble  met  with  in  building  on  rock  is  the  presence 
of  water.  As  the  surface  water  cannot  readily  penetrate  the  rock,  it 
collects  on  top  of  the  ledge  and  in  ihe  trenches,  so  that  some  arrange- 
ment for  draining  away  the  water  should  be  provided.  If  the  ledge 
falls  off  to  one  side,  a  tile  or  stone  drain  may  be  built  from  the  low- 
est point  of  the  footings  to  near  the  surface  on  the  slope.  If  in  a 
sewer  district,  the  water  may  be  drained  into  the  sewer,  using  proper 
precautions  for  trapping  and  ventilation.  If  there  is  no  sewer  and 
the  rock  does  not  fall  off,  a  pit  should  be  excavated  at  the  lowest 
part  of  the  cellar  to  collect  the  seepage,  and  an  automatic  arrange- 
ment provided  for  raising  the  water  into  a  drain  laid  above  the  sur- 
face of  the  rock. 

To  prepare  the  rock  for  the  footings,  the  loose  and  decayed  por- 
tions should  be  cut  away  and  dressed  to  a  level  surface.  If  the  sur- 
face of  the  rock  dips,  or  is  irregular  in  its  contour,  the  portion  under 
the  footings  should  be  cut  to  level  planes  or  steps,  as  shown  in 
Fig.  2.  In  no  case  should  the  footings  of  a  wall  rest  on  an  inclined 
bed. 


7.  If  there  are  fissures  or  holes  in  the  rock,  they  should  be  filled 
with  concrete,  well  rammed;  or,  if  the  fissure  be  very  deep,  it  maybe 
spanned  by  an  arch  of  brick  or  stone.     In  building  on   rock  it  is 
very  desirable  that  the  footings  shall  be  nearly  level  all  around  the 
building,  and  whenever  this  is  not  the  case  the  portions  of  the  foun- 
dation which  start  at  the  lower  level  should  be  laid  in  cement  mortar 
and  with  close  joints,  otherwise  the  foundations  will  settle  unequally 
and  cause  cracks  to  appear  above. 

8.  Should  it  be  absolutely  necessary  to  build  partly  on  rock  and 
partly  on  soil,  the  footings  on  the  soil  should  be  made  very  wide,  so 
that  the  settlement  will  be  reduced  to  a  minimum.    The  footings  rest- 
ing on  the  rock  will  not  settle,  and  the  least  settlement  in  those 
resting  on  the  soil  will  be  sure  to  produce  a  crack  in  the  superstruc- 
ture, and  perhaps  do  other  damage. 

Building   on  such  a  foundation  bed  is  very  risky  at  best,  and 
should  always  be  avoided  if  possible. 


FOUNDATIONS  ON  FIRM  SOILS.  17 

p.  Clay. — This  soil  is  found  in  every  condition,  varying  from 
slate  or  shale,  which  will  support  any  load  that  can  come  upon  it,  to 
a  soft,  damp  material,  which  will  squeeze  out  in  every  direction  when 
a  moderately  heavy  pressure  is  brought  upon  it. 

Ordinary  clay  soils,  however,  when  they  can  be  kept  dry,  will  carry 
any  usual  load  without  trouble,  but  as  a  rule  clay  soils  give  more 
trouble  than  either  sand,  gravel  or  stone. 

In  the  first  place,  the  top  of  the  footings  must  be  carried  below  the 
frost  line  to  prevent  heaving,  and  for  the  same  reason  the  outside 
face  of  the  wall  should  be  built  with  a  slight  batter  and  perfectly 
smooth.  The  frost  line  varies  with  different  localities,  attaining  a 
depth  of  six  feet  in  some  of  the  very  Northern  States,  although 
between  three-  and  four  feet  is  the  usual  depth  in  the  so-called 
Northern  States.  The  effect  of  freezing  and  thawing  on  clay  soils  is 
very  much  greater  than  on  other  soils. 

The  surface  of  the  ground  around  the  building  should  be  graded 
so  that  the  rain  water  will  run  away  from  the  building,  and  in  most 
clays  subsoil  drains  are  necessary.  When  the  clay  occurs  in  inclined 
layers,  great  care  must  be  exercised  to  prevent  it  from  sliding,  and 
when  building  on  a  side  hill  the  utmost  precautions  must  be  taken  to 
exclude  water  from  the  soil,  for  if  the  clay  becomes  wet  the  pressure 
of  the  walls  may  cause  it  to  ooze  from  under  the  footings.  The  erec- 
tion of  very  heavy  buildings  in  such  locations  must  be  considered 
.hazardous,  even  when  every  precaution  is  taken. 

Should  it  be  necessary  to  carry  a  portion  of  the  foundations  to  a 
greater  depth  than  the  rest,  the  lower  portion  of  the  walls  should  be 
built  as  described  in  Section  7,  and  care  must  be  taken  to  prevent  the 
upper  part  of  the  bed  from  slipping.  Wherever  possible,  the  footings 
should  be  carried  all  around  the  building  at  the  same  level. 

10.  In  Eastern  Maine,  where  the  soil  is  a  heavy  blue  clay,  and 
freezes  to  the  depth  of  four  feet,  it  is  customary  to  build  the  founda- 
tion walls  as  shown  in  Fig.  3,  the  footings  being  laid  dry,  to  act  as  a 
drain,  and  the  bottom  of  the  trench  being  slightly  inclined  to  one 
corner,  from  whence  a  drain  is  carried  to  take  away  the  water.     The 
portion  of  the  trench  outside  of  the  wall  is  also  filled  with  broken 
stone  or  gravel  to  prevent  the  clay  from  freezing  to  the  side  of  the 
wall.     In  the  better  class  of  work  the  outside  of  the  wall  is  plastered 
smooth  with  cement.     Sometimes  a  tile  drain  is  laid  just  outside  and 
a  little  below  the  footings. 

11.  If  the  clay  contains  coarse  sand  or  gravel  its  supporting  power 
is  increased,  and  it  is  less  liable  to  slide  or  ooze  away. 


i8 


BUILDING  CONSTRUCTION. 


In  Colorado  the  top  soil  consists  principally  of  clay,  mixed  with 
fine  sand,  and  as  long  as  it  is  kept  dry  will  sustain  a  great  load 
without  settlement.  As  soon  as  the  soil  becomes  wet,  however,  it 
turns  into  a  soft  mud,  which  is  very  compressible  and  treacherous. 
For  this  reason  the  footings  of  heavy  buildings  are  carried  through 
the  clay  to  the  sand  below.  A  peculiarity  of  this  soil  is  that, 
although  it  freezes,  it  has  never  been  known  to  heave,  so  that  two- 
story  buildings  are  often  built  directly  on  top  of  the  ground,  and  as 
long  as  water  is  kept  away  from  the  walls  no  injury  results. 

12.  Gravel. — This  material  gives  less  trouble  than  any  other  as  a 
foundation  bed.  It  does  not  settle  under  any  ordinary  loads,  and 

will  safely  carry  the  heaviest 
of  buildings  if  the  footings 
are  properly  proportioned. 
It  is  not  affected  by  water, 
provided  it  is  confined  lat- 
erally, so  that  the  sand  and 
fine  gravel  cannot  wash  out. 
This  soil  is  also  not  greatly 
affected  by  frost. 

13.  Sand.— This  mate- 
rial also  makes  an  excellent 
foundation  bed  when  con- 
fined laterally,  and  is  prac- 
tically incompressible,  as 
clean  river  sand  compacted 
in  a  trench  has  been  known 
to  support  100  tons  to  the 
square  foot. 

As  long  as  the  sand  is 
confined  on  all  sides,  and 
the  footings  are  all  on  the 
same  level,  no  trouble  what- 
ever will  be  encountered, 

unless  it  be  in  the  caving  of  the  banks  in  making  the  excavations. 
Should  the  cellar  be  excavated  to  different  levels,  however,  sufficient 
retaining  walls  must  be  erected  where  the  depth  changes  to  prevent 
the  sand  of  the  upper  level  from  being  forced  out  from  under  the 
footings,  and  precautions  should  be  taken  in  such  a  case  to  keep 
water  from  penetrating  under  the  upper  footings. 


«g.  3- 


FOUNDATIONS  ON  FIRM  SOILS. 


14.  Loam  and  Made  Land. — No  foundation  should  start  on 
loam  (soil  containing  vegetable  matter),  or  on  land  that  has  been 
made  or  filled  in,  unless,  indeed,  the  filling  consist  of  clean  beach 
sand,  which,  when  settled  with  water,  may  be  considered  equal  to  the 
natural  soil. 

Loam  should  always  be  penetrated  to  the  firm  soil  beneath,  and 
when  the  made  land  or  filling  overlies  a  firm  earth,  the  footings 
should  be  carried  to  the  natural  soil.  When  the  filled  land  is  always 
wet,  as  on  the  coast  or  the  borders  of  a  lake,  piles  may  be  used,  ex- 
tending into  the  firm  earth,  and  the  tops  cut  off  below  low  water 
mark;  but  piles  should  never  be  used  where  it  is  not  certain  that  they 
will  be  always  wet. 

15.  Mud  and  Silt. — Under  this  heading  may  be  included  all 
marshy  or  compressible  soils  which  are  usually  saturated  with  water. 

Foundations  on  such  soils  are  generally  laid  in  one  of  the  three 
following  ways:  i.  By  driving  piles  on  which  the  footings  are  sup- 
ported. 2.  By  spreading  the  footings  either  by  wooden  timbers  or 
steel  beams  so  as  to  distribute  the  weight  over  a  large  area.  3.  By 
sinking  caissons  or  steel  wells,  filled  with  masonry,  to  hard  pan.  As 
all  of  these  methods  are  more  or  less  complicated  they  will  be 
described  in  Chapter  II. 

16.  Bearing  Power  of  Soils. — The  best  method  of  determin- 
ing the  load  which  a  particular  soil  will  bear  is  by  direct  experiment; 
but  good  judgment,  aided  by  a  careful  examination  of  the  soil — par- 
ticularly of  its  compactness  and  the  amount  of  water  it  contains — in 
conjunction  with  the  following  table,  will  enable  one  to  determine 
with  reasonable  accuracy  its  probable  supporting  power.     A  mean  of 
the  values  given  below  may  be  considered  safe  for  good  examples  of 
the  kinds  of  soils  quoted: 

TABLE  I.-BEARIKG  POWER  OF  SOILS. 


KINO   OF  MATERIAL. 

BEARING     POWER 
IN   TONS   PER 
SQUARE   FOOT.* 

MIX.           MAX. 

Rock    hard           . 

25 

5 
4 
2 
I 

8 
4 

2 

..    °-5 

30 

10 

6 
4 

2 
10 

6 

4 

i 

Rock    soft 

Clay  on  thick  beds,  alwavs  dry  

Clav    soft  ....                                        

Sand,  compact  and  well  cemented  

Sand,  clean,  dry  

Quicksand,  alluvial  soils,  etc  

ra  O.  Baker,  C.  E.,  in  "  Treatise  on  Masonry  Constructor 


ao  BUILDING  CONSTRUCTION. 

Should  it  be  desirable  to  exceed  the  maximum  loads  here  given,  or 
should  there  be  any  doubt  of  the  bearing  capacity  of  the  soil  or  lack 
of  precedent,  tests  should  be  made  on  the  bottom  of  the  trenches  in 
several  places  to  determine  the  actual  load  required  to  produce  set- 
tlement, as  described  in  Section  18. 

17.  Examples  of  Actual  Loads  and  Tests. 

On  Clay. —  The  Capitol  at  Albany,  N,  Y.,  rests  on  blue  clay  containing  from 
60  to  90  per  cent,  of  alumina,  the  remainder  being  fine  sand,  and  containing  40  per 
cent,  of  water  on  an  average.  The  safe  load  was  taken  at  2  tons  per  square  foot. 
A  load  of  5.9  tons  applied  on  a  surface  I  foot  square  produced  an  uplift  of  the  sur- 
rounding earth. 

The  Congressional  Library  at  Washington,  D.  C.,  rests  on  yellow  clay  mixed 
with  sand.  It  was  found  that  it  required  about  13^  tons  per  square  foot  to  pro- 
duce settlement,  and  the  footings  were  proportioned  for  a  maximum  pressure  of 
2j£  tons 

A  hard  indurated  clay,  containing  lime,  under  the  piers  of  a  bridge  across  the 
Ohio  River,  at  Point  Pleasant,  W.  Va.,  carries  approximately  2^  tons  per  square  foot. 

Sand. — "  In  an  experiment  in  France,  clean  river  sand  compacted  in  a  trench 
supported  100  tons  per  square  foot. 

"  The  piers  of  the  Cincinnati  suspension  bridge  are  founded  on  a  bed  of  coarse 
gravel  12  feet  below  water;  the  maximum  pressure  is  4  tons  per  square  foot. 

"The  piers  of  the  Brooklyn  suspension  bridge  are  founded  44  feet  below  the  bed 
of  the  river,  upon  a  layer  of  sand  2  feet  thick,  resting  upon  bed  rock;  the  maximum 
pressure  is  about  5^  tons  per  square  foot."  * 

18.  Methods  of  Testing. — Probably   the    easiest    method    of 
determining  the  bearing  power  of  the  foundation  bed  is  by  means  of 
a  platform  from  3  to  4  feet  square,  having  four  legs,  each  6  inches 
square.     The  platform  should  be  set  on  the  bottom  of  the  trench, 
which  should  be  carefully  leveled  to  receive  the  legs.      A  level  should 
then  be  taken  from  a  stake  or  other  bench  mark  not  liable  to  be  dis- 
turbed to  each  of  the  four  corners  of  the  platform,  and  the  platform 
then  loaded  with   dry  sand,  brick,  stone  or  pig  iron,  as  may  be  most 
convenient.     The  load  should  be  put  on  gradually,  and  frequent  lev- 
els taken  until  a  sinkage  is  shown.     From  one-fifth  to  one-half  of 
the  load  required  to  produce  settlement  is  generally  adopted  for  the 
safe  load,  according  to  circumstances.     In  testing  the  ground  under 
the  Congressional  Library  a  traveling  car  was  used,  having  four  cast 
iron  pedestals,  each  measuring  i  square  foot  at  the  base  and  set  4 
ieet  apart  each  way.     The  car  was  made  to  move  along  the  trenches, 
and  halted  at  intervals  in  such  a  way  as  to  bring  the  whole  weight  of 
the  car  and  its  load  upon  the  pedestals  which  rested  on  the  bottom 
•of  the  trench.     In  this  case  the  car  was  loaded  with  pig  lead. 

*Ira  O.  Baker,  C.  E.     American  Architect,  November  3,  1888. 


FOUNDATIONS  ON  FIRM  SOILS.  21 

The  only  objection  to  this  method  is  that  if  the  legs  do  not  settle 
evenly  it  is  impossible  to  tell  just  what  the  pressure  on  the  lowest 
corner  amounts  to,  but  it  would  not  be  safe  to  consider  it  as  more 
than  one-fourth  of  the  whole  load. 

19.  In  testing  the  soil  under  the  State  Capitol  at  Albany,  N.  Y., 
the  load  was  placed  on  a  mast  12  inches  square,  held  vertical  by 
guys,  with  a  cross  frame  to  hold  the  weights.     The  bottom  of  the 
mast  was  set  in  a  hole  3  feet  deep,  18  inches  square  at  the  top  and  14 
inches  at  the  bottom.     Small  stakes  were  driven  into  the  ground  in 
lines  radiating  from  the  centre  of  the  hole,  the  tops  being  brought 
exactly  to  the  same  level,  so  that  any  change  in  the  surface  of  the 
ground   could    readily   be   detected  and  measured  by  means  of  a 
straight-edge.     In  this  case  no  change  in  the  surface  of  the  ground 
was  noticed  until  the  load  reached  5.9  tons,  when  an  uplift  of  the 
surrounding  ground  was  noticed. 

DESIGNING  THE  FOUNDATIONS. 

20.  Knowing  the  character  and  supporting  power  of  the  soil  on 
which  he  is  to  build,  the  architect  is  prepared  to  design  his  founda- 
tion plans,  but  in  no  case  should  this  be  done  when  the  preceding 
information  is  wanting. 

In  designing  the  foundations  the  first  point  to  be  settled  will  be  the 
depth  of  the  foundations;  second,  whether  they  shall  be  built  in  piers 
or  in  a  continuous  wall;  and,  third,  the  width  of  the  foundations. 

21.  Depth. — For  isolated  buildings  on  firm  soil  the  depth  of  the 
foundations  will  generally  be  determined  by  the  depth  of  the  base- 
ment or  by  the  frost  line.     Even  where  there  is  no  frost,  and  the 
ground  is  firm,  the  footings  should  be  carried  at  least  2  feet  below 
the  surface  of  the  ground,  so  as  to  be  below  the  action  of  the  surface 
water.     In  very  few  soils,  however,  is  it  safe  to  start  the  foundations 
at  a  less  depth  than  5  feet.     (See  Section  9.) 

22.  The  depth  of  the  foundations  for  city  buildings,  built  near  the 
lot  line,  should  be  governed  by  the  local  laws  bearing  on  the  subject, 
the  character  of  the  soil,  and  probable  future  action  of  the  owners  of 
the  adjoining  property. 

In  most  cities  the  law  provides  that  the  owner  of  any  lot  excavat- 
ing below  a  certain  depth  (usually  about  10  feet)  shall  protect  the 
wall  of  the  adjoining  property  at  his  own  expense,  but  if  he  does  not 
excavate  below  that  depth  (10  feet)  then  the  adjoining  owners  must 
themselves  protect  their  property  from  falling  in. 

It  is,  therefore,  always  wise  to  provide  against  any  such  future 


22  BUILDING  CONSTRUCTION. 

expense  and  trouble  by  carrying  the  footings — at  least  those  of  the 
side  walls — to  the  prescribed  limit,  above  which  the  owner  will  be 
responsible,  even  if  the  requirements  of  the  soil  or  building  do  not 
necessitate  it.  This  precaution  is  especially  important  when  the 
building  is  erected  on  sand. 

23.  Continuous  Foundations  vs.  Piers. — It  has  been  found 
that  when  heavy  buildings  are  to  be  erected  on  soft  or  compressible 
soils,  greater  security  from  settlement  may  be  obtained  by  dividing 
the  foundation  into  isolated  piers,  as  described  in  Chapter  II. 

When  building  on  firm  soils,  however,  no  advantage  is  gained  by 
pursuing  this  method,  unless  the  walls  of  the  building  are  themselves 
composed  of  piers  with  thin  curtain  walls  between,  in  which  case  the 
foundations  under  the  piers  and  walls  should  be  built  of  different 
widths,  and  not  bonded  together,  as  described  in  Section  30. 

When  the  walls  are  continuous,  however,  and  of  the  same  thickness 
throughout,  the  foundation  should  be  continuous.  The  architect 
should  constantly  bear  in  mind  that  in  all  kinds  of  building  construc- 
tion the  simplest  methods  are  almost  always  the  best,  and  compli- 
cated arrangements  and  the  use  of  iron,  etc,  in  foundations  should 
be  avoided,  at  least  on  firm  soils. 

24.  Proportioning  the   Footings. — Whether  the  foundations 
are  continuous  or  divided  into  piers  the  area  of  the  footings  should 
be  carefully  proportioned  to  the  weight  which  they  support  and  the  bear- 
ing power  of  the  soil.     The  former  is  perhaps  the  most  important  of 
all  considerations  in  designing  the  footings.     While  the  safe  bearing 
power  of  the  soil  ought  not  to  be  exceeded,  this  is,  on  most  soils,  not 
of  so  much  importance  as  the  proportioning  of  the  footings,  so  that 
the  pressure  on  the  soil  from  every  square  foot  of  the  footings  will  be 
the  same.     If  this  condition  were  always  obtained  there  would  be  few 
cracks  in  the  mason  work  of  buildings,  as  such  cracks  are  caused  not 
by  a  uniform  settlement  of  an  inch  or  two,  which  with  most  build- 
ings would  not  be  noticed,  but  by  unequal  settlement. 

25.  In  proportioning  the  area  of  the  footings  the  architect  should 
carefully  compute  the  weights  coming  upon  each  pier,  and  the  weight 
of  and  loads  supported  by  the  walls,  and  record  the  same  in  a  mem- 
orandum book  for  reference. 

He  should  then  decide,  by  means  of  Section  16  and  from  an  exam- 
ination of  the  ground,  or,  if  necessary,  from  actual  tests,  the  bearing 
weight  which  it  appears  advisable  to  assume,  and  dividing  the  load 
on  the  various  footings  by  this  assumed  carrying  load  will  give  the 
proper  area  of  the  footings. 


FOUNDATIONS  ON  FIRM  SOILS.  23 

The  pressure  under  piers  supporting  a  tier  of  iron  columns  may  be 
made  10  per  cent,  more  than  under  a  brick  wall,  so  that  the  pier  may 
settle  a  little  more  to  allow  for  the  compression  in  the  joints'  of  the 
mason  work. 

26.  In  computing  the  weight  to  be  supported  by  the  footings  the 
live  (or  movable)  load  and  dead  load  should  be  computed  separately. 
In  building  on  any  compact  soil  the  object  in  carefully  proportioning 
the  footings,  as  has  been  stated,  is  not  so  much  to  prevent  any  set- 
tling of  the  building  as  a  whole,  but  to  provide  for  a  uniform  settling 
of  all  portions  of  the  building,  so  that  the  floors  may  remain  level  and 
no  cracks  be  developed  in  the  walls.  In  order  to  secure  this,  it  is 
necessary  that  the  loads  for  which  the  footings  are  proportioned 
should  be  as  near  the  actual  conditions  as  possible.*  Thus  the  dead 
load  under  the  walls  of  a  five-story  building  would  be  a  considerable 
item,  while  the  dead  load  under  a  tier  of  iron  columns  would  be 
much  less  in  proportion  to  the  floor  area  supported,  and,  as  the  dead 
load  is  always  constant  and  the  live  load  may  vary  greatly,  only  the 
amount  of  live  load  that  will  probably  be  supported  by  the  footings 
most  of  the  time  should  be  considered. 

For  warehouses,  stores,  etc.,  about  50  per  cent,  of  the  live  load  for 
which  the  floor  beams  are  proportioned  should  be  added  to  the  dead 
load  supported  on  the  footings. 

For  office  buildings,  hotels,  etc.,  the  weight  of  the  people  who  may 
occupy  them  should  be  neglected  altogether  in  proportioning  the 
footings,  and  only  about  15  pounds  per  square  foot  of  floor  allowed 
to  cover  the  weight  of  furniture,  sa/es,  books,  etc.  [Actual  statistics 
show  that  the  permanent  average  loads  in  such  buildings  do  not  exceed 
the  above  limit.] 

For  theatres  and  similar  buildings  some  allowance  should  probably 
be  made  for  the  weight  of  people,  the  actual  amount  depending  upon 
the  arrangement  of  the  plan  and  the  character  of  the  soil. 

Almost  any  soil,  after  it  has  been  compacted  by  the  dead  weight  of 
a  building,  will  carry  a  shifting  load  of  people  without  further  settle- 
ment, while  if  the  footings  were  computed  to  carry  the  full  live  loads 
for  which  the  floor  beams  were  designed,  it  would  be  found  that 
when  the  building  was  finished  the  actual  loads  on  the  footings  under 
the  walls  would  be  much  greater  than  under  the  interior  piers,  and 
if  the  ground  had  settled  at  all  during  building,  the  probabilities 

*  Foundations  shall  be  proportioned  to  the  actual  average  loads  they  will  have  to  carry  in  the 
completed  and  occupied  building,  and  not  to  theoretical  or  occasional  loads. — Chicago  Building 
Ordinance. 


84  BUILDING  CONSTRUCTION. 

would  be  that  the  floors  of  the  building  would  be  higher  in  the  cen- 
tre than  at  the  walls. 

27.  Example  I. — We  will  suppose  that  a  six-story  and  basement 
warehouse  is  to  be  erected  on  an  ordinary  sand  and  gravel  founda- 
tion. The  building  will  be  50  feet  wide,  with  two  longitudinal  rows 
of  columns  and  girders.  What  should  be  the  width  of  the  footings 
under  the  walls  and  columns? 

Answer. — For  the  load  on  one  lineal  foot  of  footing  under  the  side 
walls  we  will  have  about  140  cubic  feet  of  brick  and  stone  work, 
weighing  about  17,000  pounds.*  One  lineal  foot  of  wall  will  also 
support  about  8  square  feet  of  each  floor  and  the  roof.  We  will 
assume  that  the  floors  are  of  iron  beams  and  terra  cotta  tile,  with  con- 
crete filling,  weighing  altogether  75  pounds  to  the  square  foot,  and 
the  roof  of  the  same  material,  weighing  60  pounds.  Then  the  dead 
load  from  the  six  floors  and  roof  would  amount  to  4,080  pounds. 
The  first,  second  and  third  floors  are  intended  to  support  150  pounds 
to  the  square  foot,  and  those  above  100  pounds- per  square  foot.  The 
possible  weight  of  snow  on  the  roof  we  will  not  take  into  account. 
There  might  then  be  a  possible  live  load  on  the  footing  of  6,000 
pounds,  but  as  it  is  improbable  that  each  floor  will  be  entirely  loaded 
at  the  same  time,  and  as  some  space  must  be  reserved  for  passages, 
etc.,  the  actual  live  load  would  probably  not  exceed  for  any  length  of 
time  50  per  cent,  of  the  assumed  load,  or  3,000  pounds.  Adding 
these  three  loads  together  (the  wall,  floors  and  live  load)  we  have 
24,080  pounds  as  the  load  on  one  lineal  foot  of  footing.  We  will 
allow  6,000  pounds  (3  tons)  for  the  bearing  power  of  the  soil,  and 
dividing  the  load  by  6,000  we  have  4  feet  as  the  required  width  of 
the  footing.  The  load  on  the  footings  under  the  columns  will  con- 
sist only  of  the  weight  of  the  floors  and  the  roof  and  the  live  load, 
plus  the  weight  of  the  tier  of  columns,  which  would  be  so  small  in 
proportion  to  the  other  loads  that  it  need  not  be  considered.  If  the 
columns  were  14  feet  apart  longitudinally,  each  column  would  sup- 
port 224  square  feet  of  each  floor,  so  that  the  total  dead  load  on  the 
footing  under  the  columns  will  amount  to  1 14,240  pounds,  and  the  pos- 
sible live  load  to  168,000  pounds.  As  it  would  be  scarcely  possible 
for  every  foot  of  floor  on  every  floor  being  loaded  to  its  full  capacity 
at  the  same  time,  we  would  probably  come  nearer  the  actual  condi- 
tions if  we  take  only  50  per  cent,  of  the  total  live  load,  or  84,000 
pounds,  making  a  total  load  on  the  footing  of  198,240  pounds,  which 

*  For  weight  per  cubic  feet  of  materials,  see  table  in  appendix. 


FO  UN  DA  TIONS  ON  FIRM  SOILS.  25 

would  require  33  square  feet  in  the  area  of  the  footing.  But  as  there 
will  be  no  shrinkage  or  compression  in  the  iron  columns  we  had  bet- 
ter reduce  this  area  10  per  cent.,  making  30  square  feet,  or  5^  feet 
square. 

The  above  calculations  should  be  entered  in  a  memorandum  book, 
kept  for  the  purpose,  somewhat  as  follows: 

DATA  FOR  FOOTINGS. 
UNDER    ONE    FT.   OF    SIDE  WALLS.  UNDER    COLUMNS. 

Cubic  feet  of  brickwork,  108  @  120=12,960  Ibs. 
Cubic  feet  of  stonework,    28  ©150=  4,200 


Total  weight  of  wall 17,160  Ibs Nothing 

Floor  area  supported  8  rj ' i6x  14=2240' 

Weight  of  floors  per  D  '  75  Ibs. 
Weight  of  roof     per  n  *  60  Ibs. 

Total  for  six  floors  and  roof:  SIQX  8=   4,080 SIGX  224=114,240 

Live  load  per  n  ' — 

1st,  2d  and  3d  floors,  150  Ibs. 

3d,  4th  and  5th  floors,  100  Ibs. 

Total  live  load,  8  x  750=6,000 75OX  224=168,000 

50$  of  this  = 3,ooo 84,000 


Total  load 24,240 198,240 

Assumed  bearing  load,  6,000  Ibs. 

Width  of  footings  under  wall,  4  ft. ;  under  columns,  33  a  '  less  io#,  or  5'  6"  x  5'  6". 

The  front  and  rear  walls,  if  continuous,  would  not  have  to  support 
any  floor  loads,  and  the  footings  should  be  reduced  in  proportion. 
The  footings  under  the  piers  supporting  the  ends  of  the  girders  should 
also  be  separately  computed. 

28.  In  the  case  of  light  buildings  it  will  often  be  found  that  the 
computed  width  of  footings  will  be  less  than  that  required  by  the 
building  ordinance,  in  which  case  it  will  of  course  be  necessary  to 
comply  with  the  ordinances  or  building  laws.  As  a  rule,  the  footings 
under  a  foundation  wall  should  be  at  least  12  inches  wider  than  the 
thickness  of  the  wall  to  give  it  stability.  Even  in  light  buildings  the 
footings  under  the  different  portions  of  the  buildings  should  be  care- 
fully proportioned,  so  that  all  will  bring  the  same  pressure  per  square 
foot  on  the  ground.  In  cases  where  the  width  of  the  footing  is  reg- 
ulated by  the  building  law,  the  pressure  per  square  foot  under  the 
footing  should  be  computed,  and  the  footings  under  all  piers,  etc., 
proportioned  to  this  standard.  In  cases  where  a  high  tower  adjoins 
a  lower  wall  the  footings  under  the  two  portions  must  be  carefully 
proportioned  to  the  weight  on  each,  otherwise  the  wall  may  crack 
where  it  is  bonded  into  the  tower. 

Example  II. — To  illustrate  the  manner  in  which  the  width  of  the 
footings  should  be  proportioned  when  the  pressure  under  the  footings 


26 


BUILDING  CONSTRUCTION. 


is  very  light,  we  will  take  the  case  of  a  one-story  stone  church,  hav- 
ing side  walls  20  inches  thick  and  22  feet  high  above  the  footings, 
and  a  tower  at  the  corner  60  feet  high,  the  first  22  feet  being  24 
inches  thick  and  the  balance  20  inches  thick.  The  roof  is  supposed 
to  be  supported  by  trusses  and  purlins,  so  that  only  the  lower  6  feet 
of  the  roof  rests  on  the  side  walls.  The  side  walls  also  carry  6  feet 
of  the  floor;  the  tower  has  a  flat  roof  12  feet  square. 

The  computations  for  the  weights  on  the  soil  under  the  side  walls 
and  under  the  tower  wall  would  be  as  follows: 


UNDER   SIDE  WALLS. 
Stonework,    22'  x  20"=  36% 

cu.ft.  at  1 50  Ibs.  percu.ft.,   5,500  Ibs. 
Weight  of  first  floor, 

130  Ibs.  x  6n  '=       780    " 
Weight  of  roof  below  purlin, 

40  Ibs.  x6a  '  =       240    " 


UNDER   TOWER    WALL. 

Stonework,    22'  x  24"=  ...       44  cu.  ft. 
38'X22"=  ...       63%  " 


107%  x  150= 16,  loo  Ibs. 

Weight  of  floor,  130x6=..         780    " 
Weight  of  roof,     40  x  6  =  . .         240    " 

Total  weight  on  soil 17,120    " 


Total  weight  on  soil 6,520    ' 

Width  of  footings,  3  ft. 

Pressure  per  a  '  under  footings,  2,173  lt>s. 

Width  of  footings  under  tower,  17, 120-=-  2, 173  =  7.8  ft. 

In  this  case  the  width  of  the  footings  under  the  side  wall  should 
be  determined  by  the  question  of  stability,  and  should  not  be  less 
than  3  feet.  Then  if  the  pressure  under  the  tower  were  reduced  to 
the  same  unit  per  square  foot,  the  tower  footings  would  need  to  be 
nearly  8  feet  wide.  On  firm  soils,  however,  such  as  sand,  gravel,  or 
compact  clay,  it  would  not  be  necessary  to  make  the  footings  so  wide 
as  this,  as  the  soil  would  probably  not  settle  appreciably  under  a  con- 
siderably greater  pressure,  so  that  if  the  footings  of  the  tower  were 
made  6  feet  wide,  thece  would  probably  be  no  danger  of  unequal  set- 
tlement. Of  course  the  greater  the  unit  pressure  on  the  soil  the  more 
exact  must  be  the  proportioning  of  the  footings. 

29.  Centre  of  Pressure  to  Coincide  with  Centre  of 
Base. — That  the  walls  and  piers  of  a  building  may  settle  uniformly 
without  producing  cracks  in  the  superstructure,  it  is  not  only  essen- 
tial that  the  area  of  the  footings  shall  be  in  proportion  to  the  load 
and  the  bearing  power  of  the  soil,  but  also  that  the  centre  of  pressure 
(a  vertical  line  through  the  centre  of  gravity  of  the  weight)  shall  pass 
through  the  centre  of  the  area  of  the  foundation. 

This  condition  is  of  the  first  importance,  for  if  the  centra  of  pres- 
sure does  not  coincide  with  the  centre  of  the  base,  the  ground  will 
yield  most  on  the  side  which  is  pressed  most,  and  as  the  ground 
yields  the  base  assumes  an  inclined  position  and  carries  the  lower 


FOUNDATIONS  ON  FIRM  SOILS. 


27 


part  of  the  structure  with  it,   thus  producing  unsightly  cracks,  if 
nothing  more. 

A  case  in  which  a  violation  of  this  rule  cannot  well  be  avoided  is 
the  foundation  under  the  side  wall  of  a  building,  where  the  footing  is 
not  allowed  to  project  beyond  the  lot  line.  In  such  a  case  the  cen- 
tre of  pressure  is  indicated  by  the  downward  arrow,  and  the  centre  of 
base  by  the  upward  arrow,  Fig.  4.  It  is  evident  that  the  intensity  of 
the  pressure  is  greatest  on  the  portion  of  the  footing  to  the  right  of 
the  centre  of  base,  and  the  footing  will  in  consequence  settle  ob- 
liquely as  shown  in  the  figure,  having  a  tendency  to  throw  the  wall 
outward.  This  tendency  may  be  counteracted  by  tying  the  wall  se- 
curely to  the  floor  joist,  but  it  would  be  much  better  if  some  arrange- 
ment could  be  made  so  that  the  footing  would  settle  evenly.  Where 


Fig.  4. 


Fig.  5. 


it  is  absolutely  necessary  to  build  the  footing  without  projecting  be- 
yond the  lot  line,  the  footing  should  be  carefully  built  of  dimension 
stone,  or  of  hard  brick,  well  grouted  in  cement  mortar,  and  the  foot- 
ing should  be  no  wider  than  is  absolutely  demanded  by  the  nature  of 
the  soil,  and  the  offsets  on  the  inside  of  the  wall  should  be  very 
slight.  The  footing  shown  in  Fig.  4  is  to  be  preferred  to  that  shown 
in  Fig.  5.  - 

30.  Fig.  6  illustrates  another  case  where  the  centre  of  pressure 
comes  outside  the  centre  of  base,  consequently  the  wall  inclines  out- 
ward, producing  cracks  over  the  opening.  This  is  a  very  common 
occurrence  in  brick  and  stone  walls  where  wide  openings  occur.  In 
such  cases  the  footing  under  the  opening  should  either  be  omitted 
entirely  or  made  much  narrower  than  under  the  pier,  and  the  two 
should  not  be  bonded  together.  Where  several  openings  occur  one 


28 


BUILDING  CONSTRUCTION. 


above  the  other,  as  in  Fig.  7,  and  the  footing  is  continued  under  the 
opening,  the  unequal  settlement  of  the  footings  will  very  likely  pro- 
duce cracks  over  all  the  openings,  the  side  walls  inclining  slightly  out- 
ward. Where  the  width  of  the  opening  is  8  feet  or  more,  and  the  bot- 
tom of  the  opening  is  not  a  great  ways 
above  the  footing,  the  footing  under 
the  wall  on  each  side  should  be  treated 
as  under  a  pier,  as  shown  in  Fig.  8, 
and  the  space  between  the  footings 
filled  in  with  a  dwarf  wall  only.  If 
the  bottom  of  the  opening  is  twice  its 
width  above  the  foundation,  the  wall 
under  the  opening  will  distribute  the 
\  weight  equally  over  the  footing  and 
the  settlement  will  be  uniform. 

As  a  rule  the  foundation  of  a 
wall  should  never  be  bonded  into 
that  of  another  wall  either  much 


i 


Fig.  6. 


heavier  or  much  lighter  than  itself. 

The  footings  should    also  be  proportioned  so  that  the  centre  of 
pressure  will  strike  a  little  inside  of  the  centre  of  the  base,  to  make 


M— i 


t 


Fig.  7- 


Fig.  8. 


sure  that  it  will  not  be  outside.  Any  inward  inclination  of  the  wall 
is  rendered  impossible  by  the  interior  walls  and  the  floors,  while  an 
outward  inclination  can  be  conteracted  only  by  anchors  and  the  bond 
of  the  masonry.  A  slight  deviation  of  the  centre  of  the  pressure  out- 
side of  the  centre  of  the  base  has  a  marked  effect,  and  is  not  easily 
counteracted  by  anchors. 


FOUNDATIONS  ON  FIRM  SOILS.  29 

At  Chicago  an  omission  of  i  to  2  per  cent,  of  the  weight  (by 
leaving  openings)  usually  causes  sufficient  inequality  in  the  settle- 
ment to  produce  unsightly  cracks.* 

Where  slight  differences  in  weight  occur,  cracks  may  generally  be 
prevented  by  building  in  hoop  iron  ties,  rods  or  beams  over  the  open- 
ings. It  is  also  a  wise  precaution,  where  one  wall  joins  another,  either 
in  the  middle  or  at  the  corner  of  a  building,  to  tie  the  walls  together 
by  long  iron  anchors  built  into  the  walls  about  every  six  feet  in 
height. 

SUPERINTENDENCE. 

31.  In  inspecting  the  excavation  the  superintendent  should  first 
examine  the  lines  to  see  that  the  building  has  been  correctly  staked 
out,  and  that  the  excavation  is  being  carried  at  least  6  inches  outside 
of  the  wall  lines,  so  as  to  give  room  for  pointing  or  cementing.  If 
the  wall  is  built  against  the  bank  it  will  be  impossible  to  point  up  the 
joints  on  the  outside,  and  the  back  of  the  wall  not  being  exposed, 
the  masons  are  apt  to  slight  that  part  of  the  work  to  the  future  detri- 
ment of  the  building ;  and  if  the  excavation  is  not  made  large 
enough  at  first,  it  causes  much  trouble  and  vexation,  as  the  work  can- 
not be  done  as  cheaply  afterward,  and  the  stone  masons  will  very 
likely  complain  about  being  delayed. 

The  superintendent  should  also  see  that  the  finished  grade  is 
plainly  marked  on  some  fixed  object  and  caution  the  workmen  not  to 
dig  the  trenches  below  the  level  marked  on  the  drawings.  If  the 
trenches  are  excavated  below  the  proper  level,  they  must  not  be 
refilled  with  earth,  as  the  footings  should  start  on  the  solid  bottom  of 
the  trench;  as  this  will  require  more  masonry  than  the  contractor 
estimated  on,  he  will  be  quite  sure  to  call  for  an  extra  payment  for 
the  same  from  the  owner,  unless  the  excavating  is  included  in  his 
contract,  in  which  case  he  will  have  to  settle  with  the  excavator. 
For  this  reason  it  is  a  good  plan  to  have  the  excavating  included  in 
the  contract  for  the  foundation. 

The  superintendent  should  also  examine  the  character  of  the  soil 
at  the  bottom  of  the  excavation,  and  if  it  is  not  such  as  was  expected, 
the  foundations  must  be  changed  or  carried  deeper,  as  previously 
described.  Should  water  be  encountered  in  making  the  excavation 
some  provision  should  be  made  for  draining  the  cellar,  either  by  lay- 
ing a  tile  drain  around  the  footings,  or  by  laying  the  bottom  courses 
dry  and  connecting  with  a  stone  drain,  as  described  in  Sections  6  and  10. 

*Prof.  Ira  O.  Baker,  C.  E.,  in  "  Masonry  Construction." 


30  BUILDING  CONSTRUCTION. 

The  specifications  should  provide  that  the  contractor  is  to  keep 
the  trenches  free  from  water  while  the  wall  is  being  laid.  In  places 
where  the  water  cannot  be  drained  off,  it  must  be  removed  by  a 
pump,  either  worked  by  hand  or  by  steam.  When  the  excavation  is 
made  close  to  an  adjoining  building  the  superintendent  should  see 
that  the  contractor  has  made  proper  provision  for  shoring  or  other- 
wise protecting  the  adjacent  walls. 


CHAPTER  II. 
FOUNDATIONS  ON  COMPRESSIBLE  SOILS. 


32.  The  soils  of  this  class  that  are  met  with  in  preparing  the  foun- 
dations of  buildings  are  generally  along  the  shore  of  some  large  body 
of  water,  and  hence  generally  permeated  with  water  to  within  a  few 
feet  of  the  surface. 

For  such  soils  pile  foundations  are  usually  the  cheapest  and  most 
reliable.  On  a  soil  such  as  underlies  Chicago,  and  having  a  support- 
ing power  of  from  \l/z  to  2/^  tons  per  square  foot,  spread  founda- 
tions may  be  used  with  satisfactory  results  and  with  economy,  when 
it  would  require  piles  over  40  feet  long  to  reach  hard  pan. 

Occasionally  it  is  necessary  to  build  on  ground  that  has  been  filled 
in  to  a  considerable  depth,  and  in  which  water  is  not  present,  or  the 
building  may  be  so  heavy  that  it  is  impracticable  to  support  it  on 
piles:  in  such  cases  wells  of  solid  masonry,  with  an  iron  casing,  or 
pneumatic  caissons,  should  be  sunk  to  bed  rock  or  hard  pan,  as 
hereinafter  described. 

PILE  FOUNDATIONS. 

When  it  is  required  to  build  on  a  compressible  soil  that  is  con- 
stantly saturated  with  water  and  of  considerable  depth,  the  cheapest 
and  generally  the  best  foundation  bed  is  obtained  by  driving  piles. 

33.  Classes  of  Piles. — A  great  many  kinds  of  piles  are  used  in 
engineering  works,  but  for  the  foundations  of  buildings  it  is  very  sel- 
dom, if  ever,  that  any  other  than  wooden  piles  are  used. 

The  different  conditions  under  which  piles  are  used  for  supporting 
buildings  may  be  classed  as  follows: 

1.  When  the  compressible  soil  is  not  more  than  40  feet  deep  and 
overlays  a  bed  of  rock,  gravel,  sand,  or  clay,  long  piles  should  be 
driven  to  the  rock,  or  one  or  two  feet  into  the  clay  or  sand,  in  which 
case  they  may  be  considered  as  columns. 

2.  If  the  soft  soil  is  more  than  40  feet  deep  piles  varying  from  15  to 
40  feet  in  length  should  be  driven,  according  to  the  character  of  the 
soil,  the  sustaining  power  of  the  piles  depending  upon  the  friction 
between  the  pile  and  the  surrounding  soil* 


32  BUILDING  CONSTRUCTION. 

3.  Short  piles,  10  to  15  feet  long,  are  sometimes  driven,  particu- 
larly in  Southern  cities,  to  consolidate  the  soil  and  give  it  greater 
resisting  power.     As  piles  are  seldom  used  in  this  way,  this  method 
of  forming  a  foundation  bed  will  be  dismissed  with  the  following 
quotation: 

34-— 

"  In  some  sections  of  the  country,  especially  in  the  Southern  cities,  the  soil  is  of 
a  soft  alluvial  material,  and  in  its  natural  state  is  not  capable  of  bearing  heavy 
loads.  In  such  cases  trenches  are  dug  as  in  firm  material,  and  a  single  or  double 
row  of  short  piles  are  driven  close  together,  and  under  towers  or  other  unusually 
heavy  portions  of  the  structure  the  area  thus  covered  is  filled  with  these  piles.  The 
effect  of  this  is  to  compress  and  compact  the  soil  between  the  piles,  and  to  a  cer- 
tain extent  around  and  on  the  outside,  thereby  increasing  its  bearing  power;  what- 
ever resistance  the  piles  may  offer  to  further  settlement  may  be  added,  though  not 
relied  upon.  These  piles  are  then  cut  off  close  to  the  bottom  of  the  trench,  and 
generally  a  plank  flooring  is  laid  resting  on  the  soil  and  piles,  or  a  layer  of  sand  or 
concrete  is  spread  over  the  bottom  of  the  trench  to  the  depth  of  6  inches  or  I  foot, 
and  the  structure,  whether  of  brick  or  stone,  commenced  on  this.  There  is  little 
or  no  danger  of  such  structures  settling,  and  if  they  do  the  chances  are  that  they 
will  settle  uniformly  if  the  number  of  piles  are  properly  proportioned  to  the  weight 
directly  above  them;  but  if  the  piles  are  not  so  proportioned,  the  same  number  be- 
ing driven  under  a  low  wall  as  under  a  high  wall,  unequal  settlement  is  liable  to 
take  place,  causing  ugly  or  dangerous  cracks  in  the  structure."* 

4.  Sheet  piles,  consisting  of  two  or  three-inch  plank  driven  close 
together,  edge  to  edge,  are  often  used  to  sustain  a  bank  during  exca- 
vation, but  are  seldom  depended  upon  for  permanent  effect. 

35.  Material. — Piles  are  made  from  the  trunks  of  trees,  and 
should  be  as  straight  as  possible,  and  not  less  than  5  inches  in  diame- 
ter for  light  buildings  or  8  inches  for  heavy  buildings.     The  woods 
generally  used  for  piles  in  the  Northern  States  are  the  spruce,  hem- 
lock, white  pine,  Norway  pine,  Georgia  pine,  and  occasionally  oak. 
In  the  Southern  States  Georgia  or  pitch  pine,  cypress  and  oak  are 
used.     Oak  is  considered  as  the  most  durable  wood  for  piles,  and  is 
also  the  toughest,  but  it  is  too  expensive  for  general  use  in  the  North- 
ern States,  besides  being  difficult  to  obtain  in  long,  straight  pieces. 
Next  to  oak  come  Georgia  pine,  Oregon  pine,  cypress  and  spruce,  in 
the  order  named. 

Of  the  1,700  piles  supporting  the  new  Illinois  Central  Railway  Station  in  Chi- 
cago, 32  per  cent,  were  black  gum,  22  per  cent,  pine,  7  per  cent,  basswood,  21  per 
cent,  oak,  15  per  cent,  hickory,  with  a  few  maple  and  elm.  A  less  proportion  of 
the  hickory  piles  were  broken  or  crushed  than  of  any  other  wood. 

36.  Pointing  and  Ringing. — Piles  should  be  prepared  for  driv- 
ing by  cutting  off  all  limbs  close  to  the  trunk  and  removing  the  bark. 

»"  A  Practical  Treatise  on  Foundations."    W.  M.  Patton,  C.  E. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       33 


The  small  end  should  be  sharpened  to  a  point  2  inches  square,  the 
bevel  being  from  18  to  24  inches  long.  The  large  end  should  be  cut 
square  to  receive  the  blows  from  the  hammer. 

Experience  has  shown  that  in  soft  and  silty  soils  the  piles  can  be 
driven  in  better  line  without  pointing.  A  pointed  pile,  on  striking  a 
root  or  similar  obstruction,  will  inevitably  glance  off,  and  no  avail- 
able power  can  prevent  it;  while  a  blunt  pile  will  cut  or  break  the 
obstruction  without  being  diverted  from  its  position. 

Piles  that  are  to  be  driven  in,  or  exposed  to,  salt  water  should  be 
thoroughly  impregnated  with  creosote,  dead  oil  of  coal  tar,  or  some 
mineral  poison  to  protect  them  from  the  "  teredo  "  or  ship  worm, 

which  will  completely  honey- 
comb an  ordinary  pile  in 
three  or  four  years. 

Ringing. — When  the  pene- 
tration at  each  blow  is  less 
than  6  inches,  the  top  of  the 
pile  should  be  protected 
from  "  brooming "  by  put- 
ting on  an  iron  ring  about  i 
inch  less  in  diameter  than 
the  head  of  the  pile,  and 
from  2^  to  3  inches  wide  by 
y%  inches  thick.  It  is  better 
to  chamfer  the  head  so  the 
ring  will  just  fit  on  than  to 
drive  the  ring  into  the  wood 
by  the  hammer,  as  the  latter 
method  is  liable  to  split  long 
pieces  from  the  pile. 

When  driving  into  compact  soil,  such  as  sand,  gravel  or  stiff  clay, 
the  point  of  the  pile  is  often  shod  with  iron,  either  in  the  form  of 
straps  bolted  to  the  end  of  the  pile,  as  at  a,  Fig.  9,  or  by  a  conical 
cast  steel  shoe  about  5  inches  in  diameter  and  having  a  i/^-inch 
dowel  12  inches  long  fitting  into  a  hole  in  the  end  of  the  pile  and  a 
ring  put  around  the  pile,  as  shown  at  b,  to  prevent  it  from  splitting. 
The  latter  method  should  be  used  in  very  hard  soils.  If  straps  are 
used,  as  at  a,  they  should  be  2^2  inches  wide,  YZ  inch  thick  and  4 
feet  long. 

37.  Manner  of  Driving. — The  usual  method  of  driving  piles  is 
by  a  succession  of  blows  given  with  a  block  of  cast  iron  called  the 


Fig.  9. 


34  BUILDING  CONSTRUCTION. 

hammer,  which  works  up  and  down  between  the  uprights  ot  a  frame 
or  machine  called  a  pile-driver.  The  machine  is  placed  over  the 
pile,  so  that  the  hammer  descends  fairly  on  its  head,  the  piles  always 
being  driven  with  the  small  end  down.  The  hammer  is  generally 
raised  by  steam  power,  and  is  dropped  either  automatically  or  by 
hand.  The  usual  weight  of  the  hammers  used  for  driving  piles  for 
building  foundations  is  from  1,200  to  1,500  pounds,  and  the  fall 
varies  from  5  to  20  feet,  the  last  blows  being  given  with  a  short  fall. 

In  driving  piles  care  should  be  taken  to  keep  them  plumb,  and 
when  the  penetration  becomes  small  the  fall  should  be  reduced  to 
about  5  feet,  the  blows  being  given  in  rapid  succession. 

Whenever  a  pile  refuses  to  sink  under  several  blows,  before  reach- 
ing the  average  depth,  it  should  be  cut  off  and  another  pile  driven 
beside  it. 

When  several  piles  have  been  driven  to  a  depth  of  20  feet  or  more 
and  refuse  to  sink  more  than  ^  inch  under  five  blows  of  a  1,200 
pound  hammer  falling  15  feet,  it  is  useless  to  try  them  further,  as  the 
additional  blows  only  result  in  brooming  and  crushing  the  head  and 
point  of  the  pile,  and  splitting  and  crushing  the  intermediate  portions 
to  an  unknown  extent. 

"  Sometimes  piles  drive  easily  and  regularly  to  a  certain  depth,  and 
then  refuse  to  penetrate  farther;  this  may  be  caused  by  a  thin  stra- 
tum of  some  hard  material,  such  as  cemented  gravel  and  sand  or  a 
compact  marl.  It  may  require  many  hard  and  heavy  blows  to  drive 
through  this,  thereby  injuring  the  piles,  and  perhaps  getting  into  a 
quicksand  or  other  soft  material,  when  the  pile  will  drive  easily  again. 
If  the  depth  of  the  overlying  soil  penetrated  is  sufficient  to  give  lat- 
eral stability,  or  if  this  can  be  secured  by  artificial  means,  such  as 
throwing  in  broken  stone  or  gravel,  it  would  seem  unwise  to  endeavor 
to  penetrate  the  hard  stratum,  and  the  driving  should  be  stopped 
after  a  practical  refusal  to  go  with  two  or  three  blows.  The  thick- 
ness of  this  stratum  and  nature  of  the  underlying  material  should  be 
either  determined  by  boring  or  by  driving  a  test  pile,  to  destruction 
if  necessary.  In  the  latter  case  the  driving  of  the  remaining  piles 
should  cease  as  soon  as  the  hard  stratum  is  reached."* 

If  the  hard  stratum,  however,  is  only  2  or  3  feet  thick,  with 
hard  pan  not  more  than  40  or  50  feet  from  the  surface,  the  piles 
should  be  driven  to  hard  pan  for  heavy  buildings  ;  but  if  the  soft 
material  continues  for  an  indefinite  depth  below  the  hard  stratum, 
the  piles  should  be  stopped  when  the  stratum  is  reached.  In  such 

*  "  A  Practical  Treatise  on  Foundations."     W.  M.  Patton,  C.  E. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       35 

cases,  however,  the  actual  bearing  power  of  the  piles  should  be  tested 
by  loading  one  or  more  of  the  piles,  as  described  in  Section  40. 

38.  Bearing  Power  of  Piles. — When  driven  in  sand  or  gravelr 
or  to  hard  pan,  piles  will  carry  to  the  full  extent  of  the  crushing; 
strength  of  the  timber,  providing  the  depth  of  the  pile  is  sufficient  to- 
secure  lateral  stiffness. 

"  There  are  examples  of  piles  driven  in  stiff  clay  to  the  depth  of  20 
feet  that  carry  from  70  to  80  tons  per  pile  :  there  are  many  instances 
in  which  piles  carry  from  20  to  40  tons  under  the  above  conditions. 
After  a  pile  has  been  driven  to  20  feet  in  sand  or  gravel,  any  further 
hammering  on  the  piles  is  a  waste  of  time  and  money,  and  injurious 
to  the  pile  itself."* 

Piles  driven  from  30  to  40  feet  in  even  the  softest  alluvial  soils 
should  carry  by  frictional  resistance  alone  from  10  to  12^2  tons. 

For  the  safe  working  loads  on  piles  driven  in  different  soils,  the 
following  table,  compiled  from  the  Engineering  News  formula,  may 
be  used  with  safety.  The  values  are  for  minimum  lengths  of  spruce 
piles  and  average  penetration  for  last  five  blows  of  a  1,200  pound 
hammer  falling  15  feet.  When  heavier  loads  than  these  must  be 
carried,  or  the  penetration  is  much  greater,  the  actual  bearing  power 
of  the  piles  should  be  determined  by  testing,  unless  it  is  already 
known  from  actual  experience. 

TABLE  II.— BEARING  VALUE  OF  PILES. 


SOIL. 

PILE 
LENGTHS. 

AVERAGE 
DIAMETER 

PENETRA- 
TION. 

LOAD    IN 
TONS. 

Silt 

Ft. 
40 

Ins. 

IO 

.    Ins. 
6 

21 

Mud 

3O 

8 

2 

6* 

Soft  earth  with  boulders  or  logs  
Moderately  firm  earth  or   clay   with 

30 

3° 

8 
8 

Ii 

I 

7 

3° 

IO 

I 

3° 

8 

3° 

8 

Firm  earth  into  sand  or  gravel  

20 

8 

Firm  earth  to  rock  

20 

8 

o 

Sand 

20 

g 

Gravel 

15 

8 

When  the  penetration  is  less  than  that  given  above,  for  soft  soils- 
the  safe  loads  may  be  increased  according  to  the  Enginee  fing  News 
formula  given  in  the  next  paragraph. 


A  Practical  Treatise  on  Foundations.' 


36  BUILDING  CONSTRUCTION. 

There  have  been  several  formulae  proposed  for  determining  the  safe 
working  loads  on  piles.  Of  these,  the  latest,  known  as  the  Engineer- 
ing News  formula,  is  generally  considered  to  be  the  most  reliable. 
It  is  claimed  for  this  formula  that  it  sets  "  a  definite  limit,  high 
enough  for  all  ordinary  economic  requirements,  up  to  which  there  is 
no  record  of  pile  failures,  excepting  one  or  two  dubious  cases  where  a 
hidden  stratum  of  bad  material  lay  beneath  the  pile,  and  above  which 
there  are  instances  of  both  excess  and  failure,  with  an  increasing  pro- 
portion of  failures  as  the  limit  is  exceeded." 

The  formula  is  : 

Safe  load  in  Ibs.  =^!_* 
s+l 

in  which  w  =  weight  of  hammer  in  pounds  ;  h,  its  fall  in  feet ; 
s,  average  set  under  last  blows  in  inches. 

39.  Municipal  Regulations. — The  New  York   Building    Law 
(1892)  provides  that 

"  Piles  intended  for  a  wall,  pier  or  post  to  rest  upon  shall  not  be  less  than  5  inches 
in  diameter  at  the  smallest  end,  and  shall  be  spaced  not  more  than  30  inches  on 
centres,  or  nearer,  if  required  by  the  Superintendent  of  Buildings,  and  they  shall 
be  driven  to  a  solid  bearing. 

"No  pile  shall  be  weighted  with  a  load  exceeding  40,000  pounds. 

"The  tops  of  all  piles  shall  be  cut  off  below  the  lowest  water  line.  When 
required,  concrete  shall  be  rammed  down  in  the  interspaces  between  the  heads  of 
the  piles  to  a  depth  and  thickness  of  not  less  than  12  inches  and  for  I  foot  in  width 
outside  of  the  piles." 

The  Boston  Building  Law  requires  that 

"Where  the  nature  of  the  ground  requires  it  all  buildings  shall  be  supported  on 
foundation  piles  not  more  than  3  feet  apart  on  centres  in  the  direction  of  the  wall. 
.  .  .  .  Buildings  over  70  feet  in  height  shall  rest,  where  the  nature  of  the 
ground  permits,  upon  at  least  three  rows  of  piles,  or  an  equivalent  number  of  piles 
arranged  in  less  than  three  rows.  All  piles  shall  be  capped  with  block  granite  lev- 
elers,  each  leveler  having  a  firm  bearing  on  the  pile  or  piles  it  covers." 

In  Chicago  it  is  required  that 

"The  piles  shall  be  made  long  enough  to  reach  hard  clay  or  rock,  and  they  shall 
be  driven  down  to  reach  the  same,  and  such  piles  shall  not  be  loaded  more  than  25 
tons  to  each  pile." 

General  William  Sooy  Smith,  in  an  address  delivered  March  31, 
1892,  before  the  students  of  engineering  of  the  University  of  Illinois, 
stated  that  "  A  pile  at  the  bottom  of  a  pit  30  feet  deep  and  well  into 
hard  pan,  or  to  the  rock  where  this  is  within  reach,  can  be  safely 
relied  upon  to  sustain  from  30  to  40  gross  tons." 

40.  Experiments  on  the  Bearing  Power  of  Piles. — The 
following  description  of  several   tests  made  to  determine  the  actual 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       37 

sustaining  power  of  piles  in  various  localities  gives  a  good  idea  of  the 
manner  of  making  such  tests,  as  well  as  the  loads  which  it  required 
to  sink  them  : 

Chicago  Public  Library. — To  determine  the  actual  resistance  of  the  piles 
on  which  it  was  proposed  to  erect  the  Public  Library  building  in  Chicago,  the 
following  test  was  made:  In  order  to  make  the  experiment  under  the  same  con- 
ditions as  would  exist  under  the  structure  three  rows  of  piles  were  driven  into  the 
trench,  the  piles  in  the  middle  row  being  then  cut  off  below  the  level  at  which 
those  in  the  outside  row  were  cut  off,  so  as  to  bring  the  bearing  only  on  four  piles, 
two  in  each  outside  row.  This  gave  the  benefit  arising  from  the  consolidation  of 
the  material  by  the  other  piles.  The  piles  were  of  Norway  pine,  54  feet  long,  and 
were  driven  about  52^  feet— about  27  feet  in  soft,  plastic  clay,  23  feet  in  tough, 
compact  clay,  and  2  feet  in  hard  pan.  They  had  an  average  diameter  of  13  inches 
and  area  at  small  end  of  80  square  inches. 

On  top  of  the  four  outside  piles,  which  were  spaced  5  feet  apart  on  centres, 
15-inch  steel  I-beams  were  placed,  and  upon  these  a  platform,  7x7  feet,  composed 
of  I2xi2-inch  yellow  pine  timbers.  On  this  platform  pig  iron  was  piled  up  at 
irregular  intervals.  When  4  feet  high  the  load  was  45,200  pounds,  and  was  then 
continued,  until  at  the  end  of  about  four  days  it  was  21  feet  high,  giving  a  load  of 
224,500  pounds.  Levels  were  taken,  but  no  settlement  had  occurred.  By  the  end 
of  about  eleven  days  the  pile  of  iron  had  reached  the  height  of  38  feet,  giving  a 
load  of  404,800  pounds  upon  the  four  piles,  or  about  50.7  tons  per  pile.  Levels 
were  then  taken  at  intervals  during  a  period  of  about  two  weeks,  and,  no  settle- 
ment having  been  observed,  a  load  of  30  tons  was  considered  perfectly  safe. 

Perth  Amboy,  1873. — Pretty  fair  mud,  30  feet  deep.  Four  piles,  12,  14, 
15  and  1 8  inches  diameter  at  top,  6  to  8  inches  at  foot,  were  driven  in  a  square  to 
depths  of  from  33  to  35  feet.  A  platform  was  built  upon  the  heads  of  the  piles  and 
loaded  with  179,200  pounds,  say  44,800  pounds  per  pile.  After  a  few  days  the 
loads  were  removed.  The  i8-inch  pile  had  not  moved,  the  12-inch  pile  had  set- 
tled 3  inches,  and  the  14  and  15-inch  piles  had  settled  to  a  less  extent.* 

Buffalo,  N.  Y. — In  the  construction  of  a  foundation  for  an  elevator  at 
Buffalo,  N.  Y.,  a  pile  15  inches  in  diameter  at  the  large  end,  driven  18  feet,  bore  25 
tons  for  twenty-seven  hours  without  any  ascertainable  effect.  The  weight  was  then 
gradually  increased  until  the  total  load  on  the  pile  was  37^  tons.  Up  to  this 
weight  there  had  been  no  depression  of  the  pile,  but  with  37^  tons  there  was  a 
gradual  depression  which  aggregated  f  of  an  inch,  beyond  which  there  was  no 
depression  until  the  weight  was  increased  to  50  tons.  With  50  tons  there  was 
a  further  depression  of  |  of  an  inch,  making  the  total  depression  i^  inches.  Then 
the  load  was  increased  to  75  tons,  under  which  the  total  depression  reached  3^ 
inches.  The  experiment  was  not  carried  beyond  this  point.  The  soil,  in  order 
from  the  top,  was  as  follows  :  2  feet  of  blue  clay,  3  feet  of  gravel,  5  feet  of  stiff  red 
clay,  2  feet  of  quicksand,  3  feet  of  red  clay,  2  feet  of  gravel  and  sand  and  3  feet  of 
very  stiff  blue  clay.  All  the  time  during  this  experiment  there  were  three  pile- 
drivers  at  work  on  the  foundation,  thus  keeping  up  a  tremor  in  the  ground.  The 
water  from  Lake  Erie  had  free  access  to  the  pile  through  the  gravel,  f 

*"A  Practical  Treatise  on  Foundations." 
t"  Masonry  Construction."     Baker. 


38  BUILDING  CONSTRUCTION. 

"Subsequent  use  shows  that  74,000 pounds  is  a  safe  load." — Patton. 

Philadelphia. — At  Philadelphia  in  1873  a  pile  was  driven  15  feet  into  soft 
river  mud,  and  five  hours  after  7.3  tons  caused  a  sinking  of  a  very  small  frac- 
tion of  an  inch  ;  under  9  tons  it  sank  f  of  an  inch,  and  under  15  tons  it  sank  5  feet. 

"The  South  Street  bridge  approach,  Philadelphia,  fell  by  the  sinking  of  the 
foundation  piles  under  a  load  of  24  tons  each.  They  were  driven  to  an  absolute 
stoppage  by  a  i-ton  hammer  falling  32  feet.  Their  length  was  from  24  to  41  feet. 
The  piles  were  driven  through  mud,  then  tough  clay,  and  into  hard  gravel."* 

The  failure  in  this  case  may  have  been  caused  by  vibrations  which  allowed  the 
water  to  work  its  way  down  the  sides  of  the  piles  and  thus  decrease  the  friction  ; 
or,  what  is  more  probable,  the  last  blow  was  struck  on  a  broomed  head,  which 
would  greatly  reduce  the  penetration  and  cause  the  bearing  power  to  be  overesti- 
mated. 

When  the  penetration  is  very  slight  or  unobservable,  and  the  head 
much  broomed,  the  broomed  portion  should  be  cut  off  and  the  blows 
repeated  if  the  full  load  of  the  formula  is  to  be  put  on  the  piles. 

41.  Actual  Loads  on  Piles. — The  following  examples  of  the 
actual  loads  which  are   carried   by  each  pile  under  the  buildings 
named  will  serve  as  a  guide  to  architects  erecting  buildings  in  those 
localities  : 

Boston.— Under  Trinity  Church,  2  tons  each. 

Chicago.— New  Public  Library  building,  30  tons. 

Schiller  Building,  estimated  load  55  tons  per  pile  ;  building  settled  from  i^  to 
Z\  inches. 

Passenger  Station,  Northern  Pacific  Railroad,  Harrison  Street :  piles  50  feet 
long  carry  25  tons  each  without  perceptible  settlement. 

The  enormous  grain  elevators  in  Chicago  rest  upon  pile  foundations.  Mr.  Adler 
states  that  the  unequal  and  constantly  shifting  loads  are  a  severer  test  upon  the 
foundations  than  a  static  load  of  a  twenty-story  building. 

New  Orleans. — Piles  driven  from  25  to  40  feet  in  a  soft,  alluvial  soil  carry 
safely  from  15  to  25  tons,  with  a  factor  of  safety  of  6  to  8. — Patton. 

42.  Spacing. — Piles  should  not  be  spaced  less  than  2  feet  on  cen- 
tres, nor  more  than  3  feet,  unless  iron  or  wooden  grillage  is  used. 

When  long  piles  are  driven  nearer  than  2  feet  from  centres  there  is 
danger  that  they  may  force  each  other  up  from  their  solid  bed  on  the 
bearing  stratum.  Driving  the  piles  close  together  also  breaks  up  the 
ground  and  diminishes  the  bearing  power. 

When  three  rows  of  piles  are  used  the  most  satisfactory  spacing  is 
2  feet  6  inches  from  centres  across  the  trench  and  3  feet  from  cen- 
tres longitudinally,  provided  this  number  of  piles  will  carry  the  wtight 
of  the  building.  If  they  will  not,  then  the  piles  must  be  spaced  closer 
together  longitudinally,  or  another  row  of  piles  driven,  but  in  no  case 
drive  two  piles  less  than  2  feet  apart  from  centres. 

*  Trans.  Am.  Soc.  of  C.  E.,  Vol.  VII.,  p.  264. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       39 


In  all  cases,  wherever  buildings  are  supported,  the  number  of  piles 
under  the  different  portions  of  the  building  should  be  carefully  pro- 
portioned to  the  weight  which  they  have  to  carry,  so  that  every  pile 
will  support  very  nearly  the  same  load.  This  precaution  is  of  espe- 
cial importance  when  part  of  the  piles  must  be  loaded  to  their  full 
capacity. 

43.  Cutting  Off  and  Capping. — The  tops  of  the  piles  should 
invariably  be  cut  off  below  low  water  mark,  otherwise  they  would 
soon  commence  to  decay. 

The  cutting  off  of  the  piles  in  building  foundations  is  generally 
done  by  means  of  a  large  cross-cut  saw  worked  by  two  men.  The 
tops  of  the  piles  should  be  left  true  and 
level  and  on  a  line  with  each  other.  A 
variation  of  £  an  inch  in  the  top  of  the 
piles  may  be  allowed,  but  it  should  not 
exceed  this  limit. 

Three  methods  of  capping  piles  are 
commonly  employed:  i.  By  granite 
blocks.  2.  By  concrete.  3.  By  tim- 
ber grillage. 

44.  Granite  Capping. — In  Boston 
it  is  obligatory  to  cap  the  piles  with 
blocks  of  granite,  which  rest  directly 
on  the  tops  of  the  piles.  If  the  stone 
does  not  fit  the  surface  of  the  pile,  or 
a  pile  is  a  little  low,  it  is  wedged  up 
with  oak  or  stone  wedges.  In  capping 
with  stone  a  section  of  the  foundation 
should  be  laid  out  on  the  drawings 
showing  the  arrangement  of  the  cap- 
ping stones. 

A  single  stone  may  rest  on  one,  two 
or  three  piles,  but  not  on  four,  as  it  is  practically  impossible  to  make  the 
stone  bear  evenly  on  four  piles.  Fig.  10  shows  the  best  arrangement 
of  the  capping  for  three  rows  of  piles.  Under  dwellings  and  light 
buildings  the  piles  are  often  spaced  as  in  Fig.  n,  in  which  case  each 
stone  should  rest  on  three  piles.  After  the  piles  are  capped  large 
footing  stones,  extending  in  one  piece  across  the  wall,  should  be  laid 
in  cement  mortar,  as  shown  in  Fig.  12. 

45.  Concrete  Capping. — In  New  York  a  very  common  method 
of  capping  the  piles  is  to  excavate  to  a  depth  of  i  foot  below  the  top 


Fig.  10. 


BUILDING  CONSTRUCTION. 


of  the  piles  and  i  foot  outside  of  them,  and  fill  the  space  thus  exca- 
vated solid  with  rich  Portland  cement  concrete,  deposited  in  layers 
and  well  rammed.  After  the  concrete  is  brought  level  with  the  top 
of  the  piles  additional  layers  are  laid  over  the  whole  foundation  until 
it  reaches  a  depth  of  18  inches  above  the  piles.  On  this  foundation 
bed,  the  brick  or  stone  footings  are  laid  as  on  solid  earth.  Many 
engineers  consider  this  the  best  method  of  capping.  There  is  cer- 
tainly no  question  of  its  durability,  and  it  is  believed  that  the  con- 
crete will  preserve  the  heads  of  the  piles  from  rotting,  provided  the 
water  is  at  all  times  up  to  the  bottom  of  the  concrete.  A  concrete 
beam  18  inches  thick  would  also  serve  to  distribute  the  pressure  over 


Fig.  ii. 

the  piles  better  than  the  stone  capping,  although  not  to  such  an 
extent  as  heavy  grillage.*  If  the  soil  is  at  all  firm  under  the  con- 
crete, it  will  also  assist  the  piles  in  carrying  the  load  when  concrete 
capping  is  used.  Under  very  heavy  buildings  the  space  between  the 
piles  to  the  depth  of  i  foot  should  be  filled  with  concrete,  whatever 
kind  of  capping  is  employed. 

46.  Grillage. — In  Chicago  most  of  the  buildings  having  pile  foun- 
dations have  heavy  timber  grillage  bolted  to  the  tops  of  the  piles,  and 
on  these  timbers  are  laid  the  stone  or  concrete  footings.  For  build- 
ing foundations  the  grillage  usually  consists  of  12x12  timbers  of  the 
strongest  woods  available,  laid  longitudinally  on  top  of  the  piles,  and 

bars  in  the  top  and  bottom  of  the  concrete  it   may   also  be  give* 


•  By  inserting  twisted  in 
great  transverse  strength. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       41 

strongest  woods  available,  laid  longitudinally  on  top  of  the  piles,  and 
fastened  to  them  by  means  of  drift  bolts,  which  are  plain  bars  of  iron, 
either  round  or  square,  driven  into  a  hole  about  20  per  cent,  smaller 
than  the  iron.  One-inch  round  or  square  bars  are  generally  used,  the 
hole  being  bored  by  a  f -inch  auger  for  the  round  bolts  or  a  -|-inch  auger 
for  the  square  bolts.  The  bolts  should  enter  the  pile  at  least  i  foot. 

If  heavy  stone  or  concrete  footings  are  used,  and  the  space  between 
the  piles  and  timbers  is  filled  with  concrete  level  with  the  top  of  the 
timbers,  no  more  timbering  is  required  ;  but  if  the  footings  are  to 
be  made  of  small  stones,  and  no  concrete  is  used,  a  solid  floor  of  cross 
timbers,  at  least  6  inches  thick,  for  heavy  buildings  should  be  laid  on 
top  of  the  longitudinal  capping  and  drift-bolted  to  them. 

Where  timber  grillage  is  used  it  should,  of  course,  be  kept  entirely 
below  the  lowest  recorded  water  line,  otherwise  it  will  rot  and  allow 
the  building  to  settle.  It  has  been  proved  conclusively,  however,  that 
any  kind  of  sound  timber  will  last  practically  forever  if  completely 
immersed  in  water. 

The  advantages  of  timber  grillage  are  that  the  timbers  are  easily  laid 
and  effectually  hold  the  tops  of  the  piles  in  place.  They  also  tend  to 
distribute  the  pressure  evenly  over  the  piles,  as  the  transverse  strength 
of  the  timber  will  help  to  carry  the  load  over  a  single  pile,  which  for 
some  reason  may  not  have  the  same  bearing  capacity  as  the  others. 

Steel  beams,  imbedded  in  concrete,  are  sometimes  used  to  distrib- 
ute the  weight  over  piles,  but  some  other  form  of  construction  can 
generally  be  employed  at  less  expense  and  with  equally  good  results. 

Objections  to  Pile  Foundations. — It  has  been  claimed  that 
driving  piles  in  a  soil  such  as  that  under  Chicago,  within  a  few  feet 
of  buildings  having  spread  foundations,  has  a  tendency  to  cause  the 
latter  to  settle  so  as  to  necessitate  underpinning. 

On  driving  the  first  piles  for  the  Schiller  Building  it  was  found  that 
an  adjoining  building  had  settled  6  inches,  and  it  had  to  be  raised  on 
screws. 

The  driving  of  piles  also  causes  a  readjustment  of  the  particles  of 
clay  and  sand  into  a  jelly,  thus  destroying  the  resisting  qualities. 
These  objections,  however,  are  not  of  so  much  moment  when  the 
adjoining  buildings  are  supported  by  piles. 

SPREAD  FOUNDATIONS. 

Compressible  soils  are  often  met  with  which  will  bear  from  i  to  2 
tons  per  square  foot  with  very  little  settlement,  and,  as  a  rule,  this  set- 
tlement is  uniform  under  the  same  unit  pressure  (pressure  per  square 
foot).  In  such  cases  it  is  often  cheaper  to  spread  the  foundations  so 


42  BUILDING  CONSTRUCTION. 

as  to  reduce  the  unit  pressure  to  the  capacity  of  the  soil  than  to 
attempt  to  drive  piles.  "  Spread  "  footings  may  be  built  of  concrete 
with  iron  tension  bars,  of  steel  beams  and  concrete,  or  of  timber  and 
concrete. 

48.  Concrete  with  Iron  Tension  Bars. — When  the  neces- 
sary height  can  be  obtained,  spread  footings  composed  of  Portland 
cement  concrete,  with  iron  tension  members,  have  more  qualities  to 
recommend  them  than  any  other  construction.  Such  footings  are 
easy  of  construction,  they  are  cheap,  and  their  durability  is  everlast- 
ing. The  iron  being  so  completely  imbedded  in  the  concrete  it  can- 
not rust,*  and  hence  there  is  no  possibility  of  deterioration  in  the 
footings. 

Masonry  is  undoubtedly  the  natural  material  for  foundations,  and 
the  author  believes  that  it  should  be  preferred  to  iron  or  steel  wher- 
ever practicable. 

By  the  use  of  twisted  iron  rods  the  concrete  footings  may  be  made 
of  equal  transverse  strength  as  footings  of  steel  beams,  but  they 
require  more  height. 


Fig.  13. 

Fig.  13  shows  the  most  economical  section  for  a  concrete  and 
twisted  iron  footing.  In  building  the  footings  with  steel  beams,  the 
strength  of  the  concrete  is  practically  wasted,  while  in  this  method  of 
construction  it  is  all  utilized.  It  has  been  proved  that  the  entire  ten- 
sile strength  of  the  twisted  bars  can  be  utilized,  and,  being  held  con- 
tinuously along  their  entire  length  by  the  concrete  as  a  screw  bolt  is 
held  by  the  nut,  they  neither  draw  nor  stretch,  except  as  the  concrete 
extends  with  them. 

In  building  concrete  footings,  as  shown  in  Fig.  13,  a  layer  of  con- 
crete from  3  to  6  inches  thick,  made  in  the  proportion  of  i  to 
3,  should  first  be  laid,  and  the  iron  bars  laid  on  and  tamped  down 

*  In  cutting  through  a  portion  of  a  foundation  built  of  concrete  and  iron,  and  submerged  in 
salt  water,  ten  years  after  the  work  was  done,  no  deterioration  to  the  iron  whatever  was  found. 
Iron  imbedded  in  concrete,  with  the  end  projecting,  has  been  found  bright  and  clean  after  the 
projecting  end  had  completely  rusted  away. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.      43 


into  it.  Another  layer  of  4  inches,  mixed  in  the  same  proportion, 
should  then  be  laid,  after  which  the  concrete  may  be  mixed  in  the  pro- 
portion of  one  to  six.  Each  layer  should  be  laid  before  the  preced- 
ing layer  has  had  time  to  harden,  otherwise  they  may  not  adhere 
thoroughly. 

The  author  has  prepared  Table  III.,  giving  the  strength  and  pro- 
portions of  footings  constructed  in  this  way,  which  he  believes  to  have 
a  large  margin  of  safety.  Two  sizes  of  bars  are  given,  with  the  cor- 
responding safe  loads  for  the  footings,  the  other  measurements  apply- 
ing to  both  cases.  The  measurements  in  the  third  column  refer  to 
the  width  of  the  brick  or  stone  footing  resting  on  the  concrete.  The 
greater  the  width  of  this  footing  in  proportion  to  the  width  of  the 
concrete,  the  less  will  be  the  strain  on  the  tension  rods. 

TABLE  III.— PROPORTIONS  AND  STRENGTH   OF  CONCRETE   FOOTINGS  WITH 
TWISTED  IRON  TENSION  BARS. 


WIDTH  OF 
FOOTING 
IN  FEET. 

THICKNESS 
OF  CON- 
CRETE. 

WIDTH  OF 
STONE 
FOOTING. 

DISTANCE 
BETWEEN 
CENTRES 
OF  BARS. 

fc  W 

-is 

N  Q.  m 

SAFE  LOAD 
PER  LINEAL 
FOOT. 

ta  w 
°5« 

"|« 

SAFE  LOAD 
PER  LINEAL 
FOOT. 

Ft.  In. 

Ft.  In. 

Inches. 

Inches. 

Tons. 

Inches. 

Tons. 

2O 

3   6 

6   o 

8 

2 

78 

66 

18 

3   3 

5   6 

8 

2 

76 

56 

16 

2   10 

5   o 

7 

if 

73 

50 

14 

2    8 

4   8 

7 

if 

70 

49 

12 

2    6 

4   4 

6 

if 

65 

48 

10 

2    3 

4   o 

6 

li 

65 

42 

8 

2    0 

4   o 

6 

I 

60 

, 

40 

6 

i   8 

3   6 

6 

t 

55 

29 

Piers. — Footings  for  piers  may  be  built  in  the  same  manner,  with 
two  sets  of  bars  laid  crossways  of  each  other,  and  also  diagonally,  as 
shown  in  Fig.  14.  In  the  case  of  piers  the  corners  should  be  cut  off 
at  an  angle  of  45  degrees,  as  shown.  The  same  size  of  bars  should 
be  used  for  a  pier  as  for  a  wall,  whose  footings  have  the  same  pro- 
jection beyond  the  masonry,  and  the  depth  of  the  concrete  should  be 
the  same. 

Example. — What  would  be  the  safe  load  for  a  pier  footing  14  feet 
square,  with  a  stone  footing  on  top  6  feet  square,  the  corners  being 
cut  off,  as  in  Fig.  14  ? 

Answer.— The  area  of  the  pier  footing  would  be  196—32  =  164 
square  feet,  and  the  projection  of  the  footing  beyond  the  masonry 
would  be  4  feet.  In  Table  III.  we  find  that  the  projection  of  the 
1 2 -foot  footings  is  3  feet  10  inches,  and  that  the  safe  load  for  this 


44  BUILDING  CONSTRUCTION. 

footing  (with  i£-inch  bars)  is  48  tons,  or  4  tons  per  square  foot.  If 
we  make  our  pier  of  the  same  thickness  and  use  i^-inch  bars  we 
would  have  the  same  strength  per  square  foot,  which  would  give  a 
total  safe  load  on  the  footing  of  656  tons. 

Unfortunately  this  method  of  construction,  including  all  forms  of 
concrete  construction  with  twisted  tension  rods,  has  been  patented  by 
Ernest  L.  Ransome,  of  San  Francisco,  Cal.,  and  the  rights  are  now 
owned  by  the  Ransome  &  Smith  Co.,  of  New  York,  Chicago  and  San 
Francisco,  to  whom  a  royalty  must  be  paid  when  twisted  bars  are 
used  ;  but  even  after  paying  the  royalty  it  is  much  the  cheapest  foot- 
ing for  the  strength  obtained. 


Fig.  14.— Plan  of  Pier. 

This  form  of  construction  has  been  used  to  a  considerable  extent 
in  San  Francisco. 

STEEL  BEAM  FOOTINGS. 

49.  When  it  is  necessary  to  spread  the  foundations  over  12  or  15 
feet  in  each  direction,  with  a  very  small  height  to  the  footings,  as  is 
the  case  in  Chicago,  steel  beams  must  be  used  to  furnish  the  neces- 
sary transverse  strength.  Even  when  building  on  solid  ground,  it  is 
claimed  that  iron  and  steel  footings  for  tall  buildings,  at  the  present 
price  of  steel  (1895),  are  cheaper  than  masonry  footings.  The  author 
doubts,  however,  if  steel  footings  will  prove  as  durable  as  those  of 
masonry. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS,      45 

The  manner  of  using  the  beams  is  shown  in  Figures  15  to  18.- 

In  preparing  the  footings,  the  ground  is  first  carefully  leveled  and 
the  bottom  of  the  pier  located.  If  the  ground  is  not  compact  enough 
to  permit  of  excavating  for  the  concrete  bed  without  the  sides  of  the 
pit  or  trench  falling  in,  heavy  planks  or  timbers  should  be  set  up  and 
fastened  together  at  the  corners,  and,  if  necessary,  tied  between  with 
rods,  to  hold  the  concrete  in  place  and  prevent  its  spreading  betore 
it  has  thoroughly  set.  A  layer  of  Portland  cement  concrete,  made  in 
the  proportion  of  i  to  6,  and  from  6  to  12  inches  thick,  accord- 
ing to  the  weight  on  the  footings,  should  then  be  filled  in  between  the 
timbers  and  well  rammed  and  leveled  off.  If  the  concrete  is  to  be  12 
inches  thick  it  should  be  put  in  in  two  layers.  Upon  this  concrete 
the  beams  should  be  carefully  bedded  in  i  to  2  Portland  cement 
mortar,  so  as  to  bring  them  nearly  level  and  in  line  with  each  other. 

The  distance  apart  of  the  beams,  from  centre  to  centre,  may  vary 
from  9  to  20  inches,  according  to  the  height  of  the  beams,  thickness 
of  concrete,  and  estimated  pressure  per  square  foot.  They  must  not 
be  so  far  apart  that  the  beams  will  crush  through  the  concrete  (see 
Section  53),  and  on  the  other  hand  there  must  be  a  space  of  at  least 
2  inches  between  edges  of  flanges  to  permit  the  introduction  of  the 
concrete  filling.  As  soon  as  the  beams  are  in  place  the  spaces 
between  them  should  be  filled  with  i  to  6  concrete,  the  stone 
being  broken  to  pass  through  a  i^-inch  ring,  and  the  concrete  well 
rammed  into  place,  so  that  no  cavities  will  be  left  in  the  centre.  The 
concrete  must  also  be  carried  at  least  3  inches  beyond  the  beams  on 
sides  and  ends,  and  kept  in  place  by  planks  or  timbers. 

50.  If  two  or  more  layers  of  beams  are  used,  the  top  of  each  layer 
should  be  carefully  leveled  (after  the  concrete  has  been  put  in  place) 
with  i  to  2  Portland  cement  mortar,  not  more  than  £  inch  thick 
over  the  highest  beams,  and  in  this  the  next  layer  ot  beams  should 
be  bedded,  and  so  on. 

The  stone  or  metal  base  plate  or  footing  should  also  be  bedded  in 
Portland  cement  mortar,  not  more  than  f  inch  thick,  above  the  upper 
tier  of  beams. 

After  the  base  plate  or  stone  footing  is  in  place  at  least  3  inches  of 
concrete  should  be  laid  above  the  beams  and  at  the  sides  and  ends, 
and  when  this  is  set  the  whole  outside  of  the  footings  should  be  plas- 
tered with  i  to  2  Portland  cement  mortar. 

Mr.  George  Hill,  Consulting  Engineer,  recommends  that  before  lay- 
ing the  steel  beams  two  thicknesses  of  tarred  felt  laid  in  hot  asphalt 
should  be  spread  over  the  concrete,  and  on  top  of  this  a  layer  of  rich 


46  BUILDING  CONSTRUCTION. 

cement  mortar  \\  inches  thick,  in  which  the  beams  should  be  placed. 
He  also  recommends  that  the  whole  ooting  be  covered  with  two 
coats  of  hot  asphalt. 

51.  Before  the  beams  are  laid  they  should  be  thoroughly  cleaned 
with  wire  brushes,  and,  while  absolutely  dry,  either  painted  with  iron 
paint  or  else  heated  and  coated  with  two  coats  of  asphalt.     Before 
covering  the  beams  with  the  concrete    every  portion  of  the  metal 
should  be  carefully  examined,  and  wherever  the  paint  or  asphaltum 
has  been  scraped  off  in  handling,  the  iron  should  be  thoroughly  dried 
and  the  coating  renewed. 

Every  pains  should  be  taken  to  protect  the  beams  from  rusting,  for,  when  unpro- 
tected, steel  beams  rust  very  quickly,  and  if  once  the  beams  were  subjected  to  the 
rusting  process  it  would  probably  not  be  long  before  the  building  commenced  to 
settle. 

52.  When  iron  and  concrete  foundations  were  first  used  in  Chicago 
railway  rails  were  employed,  on  account  of  their  lesser  cost,  to  give 
the  transverse  strength. 

The  footings  were  built  up  with  five  or  six  layers  of  rails,  placed  at 
right  angles  to  each  other,  each  layer  diminishing  in  number  until 
the  upper  surface  was  stepped  off  small  enough  not  to  unduly  exceed 
the  proper  size  of  the  column  base.  As  each  layer  of  rails  was  laid, 
concrete  was  filled  between  and  around  them,  and  when  completed 
the  footing  resembled  a  simple  concrete  pier. 

The  footings  under  the  Rand  and  McNally  Building  (erected  in  1891)  were  ot 
this  character,  five  layers  of  rails  being  used  in  most  of  the  footings.  In  some  of 
the  footings  the  upper  layer  consisted  of  1 2-inch  beams. 

Building  up  the  footings  in  successive  tiers,  however,  is  not  as  eco- 
nomical in  the  use  of  the  steel  as  when  two  layers  of  deep  beams  are 
used.  The  beams  being  large  and  smooth,  the  concrete  does  not 
unite  with  them  to  form  a  composite  beam,  as  is  the  case  in  the  Ran- 
some  construction  ;  therefore,  no  dependence  at  all  can  be  placed  on 
the  concrete  for  spreading  the 'weight. 

It  should  also  be  borne  in  mind  that  the  beams  spread  the  load 
over  the  ground  only  by  their  transverse  strength,  and  they  should, 
therefore,  be  used  in  the  same  way  that  they  would  be  were  the  foun- 
dation reversed,  the  wall  or  column  becoming  the  support  and  the 
ground  the  load. 

53.  When  several  beams  are  used  in  the  upper  course  or  layer 
there  is  a  tendency  to  concentrate  the  weight  on  the  outer  beams  of 
the  upper  layer,  owing  to  the  deflection  of  the  beams  below.     The 
author  therefore  advocates  the  use  of  as  few  beams  as  practicable  in 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       47 

the  upper  course,  and  where  the  conditions  will  permit  either  a  single 
built  up  girder  or  two  heavy  beams,  and  in  the  lower  course  the 
deepest  beams  consistent  with  economy.  If  the  beams  in  the  lower 
course  permit  of  a  spacing  much  greater  than  their  height,  a  layer  of 
rails  should  be  imbedded  in  the  top  of  the  concrete  to  prevent  the 
beams  from  breaking  through.  The  rails,  however,  would  in  no  way 
affect  the  stress  or  bending  action  in  the  beams. 

For  a  further  discussion  of  the  use  of  steel  beams  in  foundations,  the  reader  is 
referred  to  an  article  by  the  author  in  Architecture  and  Building  of  Aug.  24,  1895. 

Examples  of  steel  beam  and  concrete  footings  are  also  given,  with  illustrations, 
in  the  Engineering  Record  oi  December  12,  1891,  and  June  i,  1895. 

Method  of  Determining  the  Size  of  the  Steel  Beams. 

54.  A.  Under  a  Wall. — As  the  duty  of  the  beams  is  to  distribute 
the  load  coming  from  the  foundation  wall  or  base  plate  evenly  over 
the  ground,  so  that  the  pressure  on  each  square  foot  of  the  soil  will 


CROSS    SECTION. 


Fig.  15. 


be  the  same,  it  is  obvious  that  the  beams  must  have  sufficient  trans- 
verse strength  to  keep  them  from  bending,  so  that  they  will  settle  as 
much  at  the  outer  ends  as  under  the  centre.  The  effect  on  the 
beams  shown  in  Fig.  15,  when  resting  on  a  compressible  soil  and 
heavily  loaded  from  above,  is  to  cause  the  ends  of  the  beams  to  bend 
upward,  thus  straining  the  beams  most  at  the  centre  ;  the  stress  in 
the  beams  being  the  same  as  if  they  were  supported  at  the  centre  and 
loaded  with  a  distributed  load.  The  maximum  bending  moment  is 
also  the  same  as  for  a  beam  fixed  at  one  end  and  uniformly  loaded, 
so  that  the  beams  are  usually  calculated  by  the  formula  for  a  beam 
fixed  and  loaded  in  that  way. 

The  readiest  method  of  determining  the  size  of  the  beams  is  by 
computing  the  required  coefficient  of  strength  and  finding  in  the  tables 
of  the  manufacturers  the  size  of  beam  which  has  a  coefficient  equal 
to  or  next  above  the  value  obtained  by  the  formula.  The  coefficient 


48  BUILDING  CONSTRUCTION. 

of  strength,  generally  represented  by  the  letter  C,  is  given  in  the  cat- 
alogues of  the  companies  that  roll  beams,  and  may  also  be  found  in 
the  tables  of  beams  in  the  Architects'  and  Builders'  Pocket  Book. 

The  formula  for  the  coefficient  of  strength  for  beams  under  a  wall, 
as  in  Fig.  15,  and  also  for  the  lower  tier  of  beams  under  a  pier,  is 


in  which  w  represents  the  assumed  bearing  power  in  pounds  per 
square  foot ;  p,  the  projection  of  the  beam  in  feet,  and  s,  the  spacing 
or  distance  between  centres  of  beams,  also  in  feet. 

Owing  to  the  tendency  of  the  beams  in  bending,  to  concentrate  the 
load  on  the  outer  edges  of  the  masonry  footing,  and  thus  crush  them, 
which  action  would  have  the  same  effect  on  the  beam  as  lengthening 
the  arm  or  projection  (see  article  in  Architecture  and  Building  pre- 
viously referred  to),  the  author  recommends  that  when  the  course 
above  the  beams  is  of  stone,  brick  or  concrete,  at  least  one-third  the 
width  of  the  masonry  footing  be  added  to  the  actual  projection.  The 
calculations  above  indicated  will  be  more  clearly  shown  by  the  fol- 
lowing example  : 

Example  I. — A  building  is  to  be  erected  on  a  soil  of  which  the  safe 
bearing  power  is  but  2  tons,  and  the  pressure  on  each  lineal  foot  of 
wall  is  20  tons.  It  is  decided  to  build  the  footings  as  shown  in 
Fig.  15.  What  should  be  the  dimensions  and  weight  of  the  beams? 

Answer. — As  the  total  pressure  under  each  lineal  foot  of  wall  is  20 
tons,  and  the  safe  bearing  power  of  the  soil  2  tons,  the  footings  must 
be  20-1-2,  or  10  feet  wide.  We  will  use  4-foot  granite  blocks  for  the 
bottom  course  of  the  wall,  which  will  give  an  actual  projection  (P) 
of  3  feet  for  the  beams.  For  making  the  calculations  we  will  add  to 
the  actual  projection  one-third  of  4  feet,  or  16  inches,  making  the 
value  of  p  4^  feet.  We  will  assume  i  foot  for  the  spacing  of  the 
beams,  so  that  s  will  equal  i.  The  beams  must  then  have  a  coeffi- 
cient of  strength  =  4  Xo/X/2X  ^  =  4  X  4000  X  U^)2  X  1=304,000  Ibs. 
Examining  the  table  giving  the  properties  of  Carnegie  steel  beams, 
we  find  that  a  lo-inch  33-pound  steel  beam  has  a  coefficient  of  344,- 
ooo  pounds,  and  a  25-pound  beam  261,000  pounds;  therefore,  we 
must  use  33-pound  steel  beams  10  feet  long.  If  we  spaced  the 
beams  10  inches  on  centres,  s  would  equal  £  and  C  would  equal 
4X4000 X  (4i)8  Xf,  or  253,500  pounds,  which  would  enable  us  to 
use  2  5 -pound  beams,  thereby  effecting  a  saving  of  30  pounds  to  the 
lineal  foot  of  wall. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       49 


55.  To  facilitate  making  the  above  calculations,  the  Carnegie  Steel 
Company  publishes  the  following  table  giving  the  safe  projection  of 
Carnegie  steel  beams,  spaced  i  foot  on  centres,  and  for  bearing  values 
ranging  from  i  to  5  tons  : 

TABLE  IV.— SAFE  PROJECTIONS  IN  FEET  OF  STEEL  BEAMS  IN  FOUNDATIONS. 


I 

T  PER  FOOT. 

BEARING   POWER   IN  TONS  PER   SQUARE  FOOT. 

X 

1 

I 

Ii 

Ii 

2 

^ 

2* 

3 

3* 

4 

4i 

5 

Q 

£ 

In. 

Lbs. 

20 

80. 

14.0 

12.5 

ii.  5 

IO.O 

9- 

9.0 

8.0 

7-5 

7-0 

6-5 

6.0 

20 

64. 

12.5 

II.  O 

IO.O 

8.5 

8. 

8.0 

7.0 

6.5 

6.0 

6.0 

5-5 

15 

75- 

II.5 

10.5 

9-5 

8.0 

7- 

7-5 

6.5 

6.0 

6.0 

5-5 

5-0 

15 

60. 

10.5 

9-5 

8.5 

7-5 

6-5 

6.0 

5-5 

5-5 

5-0 

5.0 

15 

50- 

9-5 

8-5 

8.0 

7-0 

6. 

6.0 

5-5 

5-0 

5-0 

4-5 

•  5 

15 

41. 

8.5 

8.0 

7.0 

6.0 

6. 

5-5 

5-o 

4-5 

4-5 

4.0 

<  .0 

12 

40. 

8.0 

7-0 

6.5 

5.5 

5- 

5-0 

4-5 

4-0 

4.0 

3-5 

-5 

12 

32. 

7.0 

6  e 

6-5 
6.0 

5-5 

5.0 
A  e 

4- 

4-5 

4.0 

4-0 

3-5 

3-5 

.0 

IO 

33- 

25-5 

0.5 
5-5 

5-0 

5-5 
4-5 

4-  5 
4.0 

4- 

3-5 

3-5 

3-0 

3-P 

2.5 

•  5 

9 

27- 

5-5 

5-0 

4-5 

4.0 

4- 

3-5 

3-5 

3-0 

3-0 

2-5 

-5 

9 

21. 

5-0 

4-5 

4.0 

3-5 

3- 

3-0 

3-0 

2-5 

2-5 

2.5 

.0 

8 

22. 

5-0 

4-5 

4.0 

3-5 

3-5 

3-0 

3-0 

2-5 

2.5 

2.5 

.0 

8 

18. 

4-5 

4-0 

3-5 

3-o 

3-0 

3-0 

2.5 

2-5 

2.0 

2.0 

.0 

7 

2O. 

4-5 

4.0 

3-5 

3-0 

3-0 

3-o 

2.5 

2.5 

2.0 

2.O 

.0 

7 

15-5 

4.0 

3-5 

3-0 

2.5 

2-5 

2-5 

.0 

2.0 

2.0 

2.0 

-5 

6 

16. 

3-5 

3-0 

3-0 

2.5 

2-5 

2.0 

.0 

2.0 

1-5 

i-5 

•  5 

6 

13- 

3-0 

3-o 

2-5 

2.5 

2.0 

2.0 

.0 

i-5 

1-5 

1-5 

•  5 

5 

13- 

3-0 

2.5 

2.5 

2.0 

2.0 

2.0 

•  5 

i-5 

1.5 

1-5 

1-5 

5 

10. 
IO. 

2-5 

2  C 

2.5 

2.O 

2.0 
2.O 

2.0 
1-5 

1-5 
1  .5 

1-5 

i  .  5 

-5 
.5 

i-5 

i-5 

... 

1 

4 

7.5 

•*O 
2.0 

2.0 

i-5 

1-5 

i-5 

i-5 

Values  given  based  on  extreme  fibre  strain  of  16,000  pounds  per  square  inch. 

By  the  use  of  this  table  no  calculations  are  necessary  except  to 
determine  the  length  and  projection  of  the  beams.  If  the  beams  are 
to  be  spaced  more  or  less  than  i  foot  from  centres,  the  bearing  power 
must  be  increased  or  decreased  in  the  same  ratio  in  using  the  table. 
The  results  obtained  by  this  table  should  agree  with  the  result 
obtained  from  formula  i. 

Thus,  in  the  above  example,  to  use  the  table,  we  simply  look  down 
the  column  headed  2  until  we  find  the  projection  nearest  to  (above) 


BUILDING  CONSTRUCTION. 


4^  feet,  which  in  this  case  is  4.5,  and  opposite  it  we  find  a  lo-inch, 
33-pound  beam. 

To  use  the  table  for  a  spacing  of  10  inches  we  must  take  five-sixths 
of  the  bearing  power,  or  if  tons.  There  is  no  column  headed  if,  but 
it  would  come  between  i£  and  2.  For  i^  tons  the  projection  of  a 
lo-inch,  2 5 -pound  beam  is  4.5,  and  for  2  tons,  4  feet.  At  the  same 
ratio  the  projection  for  if  tons  would  be  about  4.3  feet. 

When  there  is  no  column  corresponding  with  the  bearing  power  it 
will  be  safer  to  use  formula  i. 

56.  B.  Beams  Under  Piers  (Fig.  16). — In  this  case  the  size  of  the 
lower  beams  are  determined  in  the  same  way  as  in  Example  I.,  the 

length  of  p  being  taken  from 
the  end  of  the  beam  to  the  cen- 
tre of  the  outer  beam  in  upper 
tier. 

For  the  upper  beams  the  load 
borne  by  each  beam  should  be 
computed  and  the  coefficient 
of  strength  determined  by  the 
formula 


STONE 
FOOTING 


(2) 


W  being  in  this  case  the  total 
distributed  load  on  either  end 
of  the  beam  in  pounds,  and 
p  the  distance  from  end  of 
beam  to  edge  of  iron  plate 
above. 

Example  II.  —  The  basement 
columns  of  a  ten-story  building 
are  required  to  sustain  a  per- 
manent load  of  400,000  pounds. 
What  should  be  the  size  of  the 
beams  in  the  footings,  the  supporting  power  of  the  soil  being  but  2 
tons  ? 

Answer.  —  Dividing  the  load  by  the  bearing  power  of  the  soil  we 
have  100  square  feet,  or  loX  10  feet,  for  the  area  of  the  footing.  We 
will  arrange  the  beams  as  shown  in  Fig.  16,  using  a  cast  iron  bearing 
plate  3  feet  square  under  the  column.  The  distance  between  the 
centres  of  outer  beams  in  upper  tier  we  will  make  32  inches,  thus 


SECTION. 

Fig.  16. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       51 

making  the  value  of  p  for  the  lower  beams  =  -- - or  3f  feet ; 

j  we  will  make  12  inches,  or  i. 

Looking  down  column  headed  2  (Table  IV.)  we  find  the  nearest 
projection  above  3!  is  4,  which  is  opposite  the  p-inch,  27-pound 
and  also  the  ic-inch,  25. 5-pound  beams.  The  latter  being  the 
lighter  and  also  the  stiffer,  we  will  use  for  the  lower  tier. 

For  the  upper  tier  we  see  that  the  five  beams  must  support  an  area 
equal  to  <z,  £,  c,  d,  which  in  this  case  equals  3^X  10  feet,  or  35  square 
feet.  As  the  pressure  on  each  foot  is  2  tons,  we  will  have  a  total 
pressure  of  70  tons  on  the  ends  of  the  five  beams,  or  14  tons  or 
28,000  pounds  on  each  beam.  Then  by  formula  2  we  find  the  coeffi- 
cient of  strength  must  =4  X  28,000  X  3^  =  392,000  pounds. 

From  the  table  of  the  Carnegie  Steel  Company's  beams  we  find 
that  the  coefficient  for  a  1 2-inch,  32-pound  beam  is  395,200  pounds; 
therefore,  we  will  use  three  1 2-inch,  32-pound  beams  and  two 

4o-pound    beams    in 
the  upper  tier. 

57.  The  deepest 
beam  for  the  weight 
should  always  be 
used,  and  unless  the 
beams  in  the  upper 
tier  have  considerable 
excess  of  strength, 
the  two  outer  beams 
should  be  heavy 
beams. 

When  the  footings 
carry  iron  or  steel 

columns  in  the  basement,  as  is  generally  the  case,  a  cast  iron  or  steel 
base*  plate  should  be  used,  as  shown  in  Figs.  17  and  18.  This  plate 
should  be  bedded  in  Portland  cement  directly  above  the  beams,  as 
described  in  Section  50. 

Two  and  even  four  columns  are  often  supported  on  one  footing,  as 
shown  in  Figs.  17  and  18.  In  such  cases  the  computation  becomes 
more  elaborate,  and  an  engineer  should  be  called  into  consultation 
unless  the  architect  is  himself  sufficiently  familiar  with  such  calcufa- 
tions. 

Fig.  19  shows  an  arrangement  in  which  a  built-up  base  plate  or 
girder  is  used  in  place  of  the  upper  tier  of  beams.  The  authoi 


52  BUILDING  CONSTRUCTION. 

believes  this  arrangement  much  better  than  that  shown  in  Figs.  16 
to  1 8. 

In  placing  the  beams,  it  is  essential  that  they  be  arranged  symmet- 
rically under  the  base  plate,  otherwise  they  will  sink  more  at  one  side 
than  at  the  other.  When  several  unequally  loaded  columns  rest  on 
the  same  footing,  the  equal  distribution  of  the  weight  on  the  soil 
becomes  a  difficult  problem. 

TIMBER  FOOTINGS. 

58.  For  buildings  of  moderate  height  timber  may  be  used  for  giv- 
ing the  necessary  spread  to  the  footings,  provided  water  is  always 
present.  The  footings  should  be  built  by  covering  the  bottom  of 
the  trenches,  which  should  be  perfectly  level,  with  2 -inch  plank  laid 


Fig.  18. 

close  together  and  longitudinally  of  the  wall.  Across  these  heavy 
timbers  should  be  laid,  spaced  about  12  inches  from  centres,  the  size 
of  the  timbers  being  proportioned  to  the  transverse  strain.  On  top  of 
these  timbers  again  should  be  spiked  a  floor  of  3  inch  plank  of  the 
same  width  as  the  masonry  footings  which  are  laid  upon  it.  A  sec- 
tion of  such  a  footing  is  shown  in  Fig.  20. 

All  of  the  timber  work  must  be  kept  below  low  water  mark,  and 
the  space  between  the  transverse  timbers  should  be  filled  with  sand, 
broken  stone  or  concrete.  The  best  woods  for  such  foundations  are 
oak,  Georgia  pine  and  Norway  pine.  Many  of  the  old  buildings  in 
Chicago  rest  on  timber  footings. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.      53 


Planed  joint. 


Fig.  19. 


inch  PlanK.. 


54  BUILDING  CONSTRUCTION. 


59.  Calculation  for  the  Size   of  the   Cross  Timbers.— 

The  size  of  the  transverse  timbers  should  be  computed  by  the  fol- 
lowing formula  : 

Breadth  in  inches  =»X«>X^XJ  ...............  ^ 

•U    X  -^i 

w  representing  the  bearing  power  in  pounds  per  square  foot  ;  /,  the 
projection  of  the  beam  beyond  the  3-inch  plank  in  feet  ;  s,  the  dis- 
tance between  centres  of  beams  in  feet,  and  D,  the  assumed  depth 
of  the  beam  in  inches.  A  is  the  constant  for  strength,  and  should 
be  taken  at  90  for  Georgia  pine,  65  for  oak,  60  for  Norway  pine  and 
55  for  common  white  pine  or  spruce. 

Example  I.  —  The  side  walls  of  a  given  building  impose  on  the 
foundation  a  pressure  of  20,000  pounds  per  lineal  foot  ;  the  soil  will 
only  support,  without  excessive  settlement,  2,000  pounds  to  the 
square  foot.  It  is  decided  for  economy  to  build  the  footings  as 
shown  in  Fig.  20,  using  Georgia  pine  timber.  What  should  be  the 
size  of  the  transverse  timbers  ? 

Answer.  —  Dividing  the  total  pressure  per  lineal  foot  by  2,000 
pounds,  we  have  10  feet  for  the  width  of  the  footings.  The  masonry 
footing  we  will  make  of  granite  or  other  hard  stone,  4  feet  wide,  and 
solidly  bedded  on  the  plank  in  Portland  cement  mortar.  The  pro- 
jection p  of  the  transverse  beams  would  then  be  3  feet.  We  will 
space  the  beams  12  inches  from  centres,  so  that  J=i,  and  will  assume 
10  inches  for  the  depth  of  the  beams.  Then  by  formula  3,  breadth 

in  inches  =  2X  2OOoX9><  *=  4>  or  we  should  use  4*X  10*  timbers,  12 
100X90 

inches  from  centres.  If  common  pine  timber  were  used  we  should 
substitute  55  for  90,  and  the  result  would  be  6£. 

60.  When  building  on  quicksand  it  is  often  advantageous  to  lay  a 
floor  of  i  -inch  boards  in  two  or  more  layers  at  right  angles  to  each 
other  on  which  to  start  the  concrete  footings. 

61.  Foundations   for   Temporary   Buildings.  —  When  tem- 
porary buildings  are  to  be  built  over  a  compressible  soil,  the  founda- 
tions may,  as  a  rule,  be  constructed  more  cheaply  of  timber  than  of 
any  other  material,  and  in  such  cases  the  durability  of  the  timber 
need  not  be  considered,  as  good  sound  lumber  will  last  two  or  three 
years  in  almost  any  place  if  thorough  ventilation  is  provided. 

The  World's  Fair  buildings  at  Chicago  (1893)  were,  as  a  rule,  sup- 
ported on  timber  platforms,  proportioned  so  that  the  maximum  load 
on  the  soil  would  not  exceed  i£  tons  per  square  foot.  Only  in  a  few 
places  over  "  mud  holes  "  were  pile  foundations  used. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       55 


The  platform  foundations  consisted  of  "3-inch  pine  or  hemlock 
planks,  with  blocking  (transverse  beams)  on  top,  to  distribute  the 
pressure  from  the  loads  uniformly  over  all  the  planks  and  to  furnish 
support  for  the  posts  which  carry  the  caps  supporting  the  floor  joists 
and  posts  of  the  building.  The  blocking  was  well  spiked  to  platform 
planks  and  posts,  and  caps  and  sills  drift  bolted." 


rift  lotta 


Fig.  21  shows  the  general  arrangement  of  the  blocking  under  the 
posts. 

MASONRY  WELLS. 

62.  When  it  is  necessary  to  support  very  heavy  buildings  on  com- 
pressible or  filled  soil,  where  piles  or  spread  footings  cannot  be  used, 
or  are  not  considered  desirable,  wells  of  masonry,  sunk  to  bed  rock 
or  hard  pan,  will  generally  prove  the  next  cheapest  method  of  secur- 
ing an  efficient  foundation.  The  wells  are  arranged  as  isolated  piers, 
and  the  walls  of  the  superstructure  carried  on  steel  girders  resting  on 
these  piers. 

The  manner  in  which  such  wells  or  piers  should  be  used  can  prob- 
ably be  best  explained  by  describing  those  under  the  City  Hall  of 
Kansas  City,  Mo.,  which  was  one  of  the  first  instances  in  which  such 
wells  were  used  in  this  country.* 


*The  following  description 
building,  Mr.  S  E.  Chamberla 
American  Institute  of  Architec 
ing-  Record  from  the  architect' 
nee-ring  Record  of  April  2  and 


an  abstract  of  a  short  paper  presented  by  the  architect    of  the 

,  of  Kansas  City,  to  the  twenty-fourth  annual  convention  of  the 

The  illustrations  were  prepared  in  the  office  of  the  Engineer- 

drawings.     Several  more   illustrations  are  given  in  the  Engi- 


5 6  BUILDING  CONSTRUCTION. 

"  The  site  of  the  City  Hall  was  formerly  a  ravine  between  abrupt  bluffs.  These 
had  been  so  cut  away  and  leveled  as  to  leave  a  so-foot  filling  of  rubbish  under  two- 
thirds  of  the  building  and  a  solid  clay  bank  under  the  other  third.  The  fill  was 
made  by  a  public  dump.  Pile  foundations  were  objectionable  on  account  of  the 
dryness  of  the  fill  and  the  anticipated  tendency  of  the  piles  to  rot  therein.  Ordi- 
nary trenching  was  considered  too  expensive  and  dangerous,  therefore  a  system  of 
piers  was  chosen,  and  a  cylindrical  form  was  adopted,  so  that  the  excavation  could 
be  done  by  a  large  steam  power  auger,  followed  by  a  -j^-inch  caisson  filled  with 
vitrified  brick.  The  caissons  were  made  in  5-foot  lengths  of  the  same  thickness 
throughout,  the  joints  being  made  with  s"x^"  splice  plates,  riveted  to  the  inside  of 
the  shell. 

"  The  piers  were  of  vitrified  brick,  4  feet  6  inches  in  diameter,  laid  in  hydraulic 
cement  mortar,  grouted  solid  in  each  course,  and  well  bonded  in  all  directions. 
The  piers  were  sunk  to  bed  rock  of  oolitic  limestone,  8  feet  thick,  and  capped  with 
cast  iron  plates  (Fig.  22)  and  steel  I-beams,  which  supported  the  walls.  To  the 
top  of  the  beams  was  riveted  a  ^-inch  plate  of  boiler  iron,  on  which  the  brickwork 
of  the  walls  was  built,  as  shown  in  Fig.  23. 

"  Between  the  beams,  and  I  foot  on  each  side  and  underneath  them,  is  a  con- 
crete filling,  so  that  the  beams  are  entirely  encased  in  masonry. 

"  Piers  having  excessive  loads  are  reinforced  by  1 2-inch  Z-bar  columns  resting 
on  rock  bottom  (Fig.  24).  These  columns  pass  through  the  cast  iron  caps,  so  that 
the  loads  resting  on  the  columns  are  separate  from  those  on  the  brick  piers  (an 
essential  provision).  Essentially  the  whole  system  is  intended  to  secure  the  direct 
transmission  of  the  entire  weight  to  the  solid  rock  by  so  arranging  the  interior  con- 
struction that  each  subdivision  is  carried  by  an  adequate  isolated  pier.  The  piers 
are  of  uniform  size,  and  their  loads  are  equalized  by  spacing  them  at  proportionate 
distances  apart." 

63.  Another  instance  of  the  use  of  masonry  wells  or  deep  piers  is 
in  the  foundation  of  the  new  Stock  Exchange  in  Chicago. 

"The  foundation  is  generally  upon  piles  about  50  feet  long,  driven  into  the  hard 
clay  which  overlies  the  rock.  Next  to  the  Herald  Building,  however,  which  adjoins 
it,  wells  were  substituted,  lest  the  shock  of  the  pile  driver  close  to  its  walls  should 
cause  settlements  and  cracks.  A  short  cylinder,  5  feet  in  diameter,  made  of  steel 
plate,  was  first  sunk  by  hand,  reaching  below  the  footings  of  the  Herald  Building. 
Then  around  and  inside  the  base  of  the  cylinder  sheet  piles,  about  3^  feet  long, 
were  driven,  and  held  in  place  by  a  ring  of  steel  inside  their  upper  ends.  The 
material  inside  the  sheeting  was  excavated  and  a  similar  steel  ring  was  placed 
inside  their  lower  ends.  By  means  of  wedges  the  lower  ends  of  the  sheeting  were 
forced  back  into  the  soft  clay  until  another  course  could  be  driven  outside  the  lower 
ring.  This  operation  was  repeated  until  the  excavation  had  reached  the  hard  clay 
about  40  feet  below  the  cellar.  In  this  material  the  excavation  was  continued 
without  sheeting  in  the  form  of  a  hollow  truncated  cone  to  a  diameter  of  7^  feet, 
and  the  entire  excavation  was  filled  with  concrete.  The  wells  are  spaced  about  12 
feet.  The  loads  upon  them  vary;  some  of  them  will  carry  about  200  tons. 

"  The  material  excavated  was  a  soft,  putty-like  clay  to  a  depth  of  40  feet,  where 
a  firm  clay  was  reached  deemed  capable  of  carrying  the  weight  proposed."  * 

*  "  Foundations  of  High  Buildings."  By  W.  R  Hutton,  C.  E.,  etc.  Read  before  the  Con- 
gress of  Architects  at  Chicago,  189). 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       57 

CAISSONS. 

64.  Although  caissons  have  been  extensively  used  in  constructing 
the  foundations  of  bridge  piers,  they  have  as  yet  been  used  for  the 
foundations  of  but  few  buildings  in  this  country,  the  first  instance 


FlO.23 


being  the  building  for  the  Manhattan  Life  Insurance  Company,  near 
the  foot  of  Broadv/ay,  New  York  City — Messrs.  Kimball  &  Thomp- 
son, Architects  ;  Charles  O.  Brown,  Consulting  Engineer. 


58  BUILDING  CONSTRUCTION. 

As  it  is  claimed  that  the  method  there  employed  proved  perfectly 
satisfactory,  and  cost  only  about  8  or  9  per  cent,  of  the  estimated  cost 
of  the  building,  it  is  deemed  of  sufficient  importance  to  merit  a  short 
description  of  the  manner  in  which  the  foundations  were  constructed 
and  the  superstructure  supported  therefrom.* 

'' The  building  occupies  an  area  of  about  8,200  square  feet,  and  is  seventeen 
stones  high  on  Broadway  and  eighteen  on  New  Street.  The  height  from  the 
Broadway  curb  to  the  parapet  of  the  main  roof  is  242  feet,  and  the  dome  and  tower 
rises  108  feet  above  the  parapet.  All  the  walls,  together  with  the  iron  floors  and 
roof  (which  are  very  heavy),  are  directly  supported  by  thirty-four  cast  iron  col- 
umns, which  sustain  an  estimated  weight  of  about  30,000  tons. 

"  The  great  height  and  massive  metal  and  masonry  construction  impose  enor- 
mous loads  on  the  foundations,  amounting  to  as  much  as  200  tons  for  some  single 
columns,  and  giving  about  7,300  pounds  per  square  foot  over  the  whole  area  of  the 
lot.  This  enormous  weight  could  not  be  safely  carried  on  the  natural  soil,  which 
is  essentially  of  mud  and  quicksand  to  the  bed  rock,  which  has  a  fairly  level 
surface  about  54  feet  below  the  Broadway  street  level.  Above  this  rock  the 
water  percolates  very  freely,  standing  at  a  level  of  about  22  feet  below  the 
Broadway  street  line,  and  therefore  making  excavations  below  this  plane  difficult 
and  costly.  If  piles  had  been  driven  as  close  together  as  the  city  regulations  per- 
mit— i.  e.,  30  inches  centre  to  centre  over  the  whole  area,  about  1,323  might  have 
been  placed,  and  would  have  carried  an  average  load  of  45,300  pounds  each,  which 
was  inadmissible,  the  statute  laws  of  New  York  allowing  only  40,000  pounds  each 
on  piles  2  feet  6  inches  apart  and  with  a  smallest  diameter  of  5  inches. 

"Special  foundations  were  therefore  necessary,  and  it  was  imperative  that  their 
construction  and  duty  should  not  jeopardize  nor  disturb  the  existing  adjacent  heavy 
buildings  which  stand  close  to  the  lot  lines.  On  the  south  side  the  six-story  Con- 
solidated Exchange  Building  is  founded  on  piles  which  are  supposed  to  extend  to 
the  rock.  On  the  north  the  foundations  of  a  four-story  brick  building  rest  on  the 
earth  about  28  feet  above  the  rock,  and  were  especially  liable  to  injury  from  dis- 
turbances of  the  adjoining  soil,  which  was  so  wet  and  soft  as  to  be  likely  to  flow  if 
the  pressure  was  much  increased  by  heavy  loading  or  diminished  by  the  excava- 
tion of  pits  or  trenches. 

"  In  view  of'these  conditions  it  was  determined  to  carry  the  foundations  on  solid 
masonry  piers  down  to  bed  rock.  The  construction  of  the  piers  by  the  pneumatic 
caisson  process  was,  after  careful  consideration  by  the  architects,  backed  by  opin- 
ions from  prominent  bridge  engineers  as  to  its  feasibility,  adopted. 

"  The  smaller  caissons  were  received  complete  and  the  larger  ones  in  conven- 
ient sections,  bolted  together  when  necessary,  and  located  in  their  exact  horizontal 
positions,  calked  and  roofed  with  heavy  beams  to  form  a  platform,  on  which  the 
brick  masonry  was  started  and  built  up  for  a  few  feet  before  the  workmen  entered 
the  excavating  chamber  and  began  digging  out  the  soil.  The  removal  of  the  soil 
allowed  the  caissons  to  gradually  sink  to  the  rock  below  without  disturbing  the 
adjacent  earth,  which  was  kept  from  flowing  in  by  maintaining  an  interior  pneu- 

*  The  following  is  an  abstract  from  a  very  full  description,  with  ten  illustrations,  published  in 
the  Engineering  Record  of  January  20,  1894. 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       59 


6o 


BUILDING  CONSTRUCTION. 


matic  pressure  slightly  in  excess  of  the  outside  hydrostatic  pressure  due  to  the  dis- 
tance of  the  bottom  of  the  caisson  below  the  water  line. 

"The  adjacent  buildings  were  shored  up  at  the  outset  and  scrupulously  watched, 
observations  being  made  to  determine  any  possible  displacement  or  injury  of  their 
walls,  which  were  not  seriously  damaged,  though  the  pressure  they  exerted  on  the 
yielding  soil  tended  to  deflect  the  caissons  which  were  sunk  within  a  foot  of  them. 
They  were  kept  in  position  by  excess  of  loading  and  excavating  on  the  edges  that 


tended  to  be  highest.  The  caissons  encountered  boulders  and  other  obstructions, 
and  were  sunk  through  the  fine  soil  and  mud  at  an  average  rate  of  4  feet  per  day. 
No  blasting  was  required  until  the  bed  rock  was  reached  and  leveled  off  under  the 
edges  and  stepped  into  horizontal  surfaces  throughout  the  extent  of  the  excavating 
chamber.  Usually  one  caisson  was  being  sunk  while  another  was  being  prepared, 
there  being  only  one  time  when  air  pressure  was  simultaneously  maintained  in  two 
caissons.  Generally  about  eight  days  were  required  to  sink  each  caisson." 


*  Published  by  consent  of  the  Engineering  Record, 


FOUNDATIONS  ON  COMPRESSIBLE  SOILS.       61 

The  first  caisson  was  delivered  at  the  site  April  13,  1893,  and  the  last  pier  was 
completed  August  13,  1893. 

"After  the  caissons  were  sunk  to  bed  rock,  and  the  surface  cleared  and  dressed, 
the  excavating  chambers  and  shafts  were  rammed  full  of  concrete,  made  of  I  part 
Alsen  Portland  cement,  2  parts  sand  and  4  parts  of  stone,  broken  to  pass  through 
a  2^-inch  ring.  The  superimposed  piers  were  built  of  hard-burned  Hudson  River 
brick,  laid  in  mortar  composed  of  i  part  Little  Giant  cement  to  2  parts  sand." 

Fig.  25  is  a  plan  showing  the  piers  (all  of  which,  except  P,  which  is  built  on 
twenty-five  piles,  are  founded  on  caissons  of  the  same  size)  and  the  bolsters  on  top 
of  them,  together  with  the  girders  and  the  columns,  which  are  indicated  by  solid 
block  cross  sections. 

"Cylindrical  caissons  are  the  most  convenient  and  economical,  and  would  have 
been  used  throughout  if  the  conditions  had  permitted,  but  the  positions  of  the  col- 
umns and  the  necessity  of  distributing  the  load  along  the  building  lines  and  other 
considerations  determined  the  use  of  rectangular  ones,  except  in  four  cases."  All 
the  caissons  were  II  feet  high,  made  of  ^-inch  and  f-inch  plates  and  6x6-inch 
angle  framework,  stiffened  with  7-inch  bulb  angles,  vertical  brackets  and  rein- 
forced cutting  edges. 

The  columns  supporting  the  outer  side  walls  of  the  building  were  located  so  near 
the  building  line  as  to  be  naar  or  beyond  the  outer  edge  of  the  foundation  piers,  as 
shown  in  Fig.  25,  so  that  if  they  had  been  directly  supported  therefrom  they  would 
have  loaded  it  eccentrically  and  produced  undesirable  irregularities  of  pressure. 
This  condition  was  avoided  and  the  weights  transmitted  to  the  centres  of  the  piers 
by  the  intervention  of  heavy  plate  girders,  which  supported  the  columns  in  the 
required  positions  and  transferred  their  weights  to  the  proper  bearings  above  the 
piers.  From  these  bearings  the  load  was  distributed  over  the  whole  area  of 
the  masonry  by  special  steel  bolsters. 

Fig.  26  is  a  transverse  section  at  D-H-M,  Fig.  25,  showing  the  quadruple 
girder  C,  17-18-19,  and  the  manner  in  which  it  supports  columns  23  and  33.  The 
cantilever  is  made  continuous  across  the  building,  with  intermediate  supports  under 
columns  21  and  22. 

Pneumatic  caisson  foundations  were  also  used  in  the  foundation 
construction  of  the  American  Surety  Building,  New  York,  a  full 
description  of  which  is  given  in  the  Engineering  Record  of  July  14, 
1894.  Caisson  foundations,  whether  in  the  shape  of  wells  or  of  the 
pneumatic  form,  should  only  be  used  under  the  advice  or  direction  of 
a  competent  engineer. 

65.  Foundations  of  High  Buildings. — In  preparing  the  foun- 
dations of  high  buildings  the  same  principles  apply  as  for  other 
buildings,  except  that  the  loads  on  the  foundations  being  so  much 
greater  the  footings  must  be  proportioned  with  the  utmost  care. 

When  building  on  firm  soils  it  is  only  necessary  to  carefully  observe 
all  the  precautions  given  in  Chapter  I.,  and  on  compressible  soils  one 
of  the  methods  described  in  this  chapter  should  be  employed,  always, 
however,  under  the  advice  of  an  experienced  engineer. 


CHAPTER  III. 

MASONRY    FOOTINGS    AND    FOUNDATION 

WALLS,  SHORING  AND 

UNDERPINNING. 

MASONRY  FOOTINGS. 

66.  Footings  under  walls  are  used  for  two  purposes:   i.  To  spread 
the  weight  over  a  greater  area.     2.  To  add  to  the  stability  of  the  wall. 
Under  buildings  of  only  two  or  three  stories,  the  latter  function  is 
generally  the  more  important. 

All  walls  should  therefore  have  a  footing  or  projecting  course  at 
the  bottom  of  either  brick,  stone  or  concrete. 

The  width  of  the  footings  should  be  at  least  12  inches  wider  than 
the  thickness  of  the  wall  above,  and  also  such  that  the  pressure  per 
square  foot  under  the  footing  will  not  exceed  the  safe  bearing  power 
of  the  soil  or  the  material  on  which  it  rests.  (See  Section  16.) 

67.  Concrete  Footings. — For  nearly  all  classes  of  buildings 
built  on  solid  ground  cement  concrete  makes  probably  the  best  mate- 
rial for  the  bottom  footing  course,  especially  for  the  money  expended. 
Concrete  possesses  the  advantage  over  large  blocks  of  stone  of  having 
considerable  transverse  strength,  so  that  when  fully  hardened  it  is 
much  like  a  wide  beam  laid  on  top  of  the  ground  under  the  walls; 
and  should  a  weak  spot  occur  in  the  ground  under  the  footing  it 
would  probably  have  sufficient  transverse  strength  to  span  it  if  the 
spot  were  not  very  large.     Concrete  must  also  necessarily  bear  evenly 
over  the  bottom  of  the  trenches,  so  that  there  can  be  no  cavities,  as 
is  sometimes  the  case  with  stone  footings.     In  localities  where  large 
blocks  of  granite  or  flagging  cannot  be  cheaply  procured,  concrete 
makes  much  the  cheapest  footing. 

In  stiff  soils  trenches  for  the  concrete  footing  should  be  dug  below 
the  general  level  of  the  excavation  and  of  the  exact  width  of  the 
footings,  so  that  when  the  concrete  is  put  in  and  tamped  it  will  bear 
against  the  sides  as  well  as  the  bottom  of  the  trench.  In  sandy  soils 
this  of  course  cannot  be  done,  and  planks  must  be  set  up  and  held  in 
place  by  stakes  to  form  the  sides  of  the  trench.  After  the  cement  has 
set,  but  not  before,  the  planks  may  be  removed. 

Concrete  for  footings  should  be  mixed  in  the  proportion  of  i  part 
cement  to  2  of  sand  and  4  of  stone  for  natural  cements,  and  i  to  zi 


MASONRY  FOOTINGS. 


and  5^  for  Portland  cement.  The  thickness  of  the  concrete  should 
be  one-fourth  of  its  width,  and  never  less  than  12  inches,  except 
under  very  light  buildings.  The  concrete  should  be  put  in  in  layers 
about  6  inches  thick.  If  the  footing  is  considerably  wider  than  the 
wall  it  may  be  stepped  in  by  setting  up  plank  to  hold  the  upper  lay- 
ers of  concrete,  or  a  stone  footing  of  proper  width  may  be  placed  on 
top  of  the  concrete,  as  in  Fig.  27.  The  latter  is  apt  to  give  the  best 
results. 

For  the  manner  of  mixing  the  concrete  see  Section  142  and  specifi- 
cations in  Chapter  X.     For  width  of  offsets  see  Section  70. 


^;^;.  Concrete.      '£.t£ 

"^i's-^i.^r^  •<*- '  !'"?£•  •swr^-f':: 

r*t •».-•  '-*•', ~"     .   -*?".' j.V^rX'' 


Fig.  27.  Fig.  28. 

68.  Stone  Footings. — For  buildings  of  moderate  height  stone 
footings  are  generally  the  most  economical,  and  if  they  are  carefully 
bedded,  answer  as  well  as  concrete. 

If  practicable,  the  bottom  footing  course  should  consist  of  single 
stones  of  the  full  width  of  the  footing,  and  the  thickness  of  the  stones 
should  be  about  one-fourth  of  their  width,  depending  much,  however, 
upon  the  kind  of  stone.  If  stone  of  sufficient  width  cannot  be 
obtained,  the  stone  may  be  jointed  under  the  centre  of  the  wall,  and 
a  second  course  consisting  of  a  single  stone  placed  on  top,  as  shown  in 
Fig.  28. 

For  light  buildings  of  only  one  qr  two  stories,  used  for  dwellings  or 
similar  purposes,  irregular  shaped  stones,  called  "  heavy  rubble,"  are 
generally  used,  as  shown  in  Fig.  29,  which  represents  a  plan  of 
the  footing  course,  the  spaces  between  the  larger  stones  being  filled 
in  with  smaller  stones.  Each  stone  should  be  laid  in  mortar  and  the 
spaces  between  the  stones  solidly  filled  with  mortar  and  broken  stone. 

Under  heavy  buildings  the  footing  stones  should  be  what  are  called 
"  dimension  stones,"  that  is,  they  are  roughly  squared  to  certain 
dimensions.  Dimension  stones  for  footings  may  be  obtained  from  4 
to  8  feet  in  length,  according  to  the  kind  of  stone.  The  width  of  the 


64 


BUILDING  CONSTRUCTION. 


stones,  measured  lengthways  of  the  wall,  should  be  at  least  2  feet,  or 
two-thirds  the  width  of  the  footings. 

The  best  stones  for  heavy  footings  are:    Granite,  bluestone,  slate 
and  some  hard  laminated  sandstones  and  limestones. 

69.  Bedding.— As  footing  stones  are  generally  very  rough,  being 
left  as  they  come  from  the  quarry,  they  cannot  be  made  to" bear  evenly 

____^ ^  _     on  the  bottom  of  trenches 

without  being  bedded 
either  in  a  thick  bed  of 
mortar,  or,  if  the  soil  is 
sand  or  gravel,  by  wash- 
ing the  sand  into  the 
As  a  rule,  the  only  safe  way 


Fig.  «9. 


spaces  by  means  of  a  stream  of  water. 

is  to  specify  that  the  stones  shall  be  set  in  a  thick  bed  of  cement 

mortar  and  worked  around  with  bars  until  it 

is  solidly  bedded. 

70.  Offsets. — The  projection  of  the  foot- 
ings beyond  the  wall,  or  the  course  above,  is  a 
point  that  must  be  carefully  considered,  what- 
ever be  the  material  of  the  footings.  \ 

If  the  projection  of  the  footing  or  offset  of  \        I 

the  courses  is  too  great  for  the  strength  of  the 
stone,  brick  or  concrete,  the  footing  will 
crack,  as  shown  in  Fig.  30. 

The  proper  offset  for  each  course  will  depend  upon  the  vertical 
pressure,  the  transverse  strength  of  the  material,  and  the  thickness  of 
the  course.  Each  footing  stone  may  be  considered  as  a  beam  fixed 
at  one  end  and  uniformly  loaded,  and  in  this  way  the  safe  projection 
may  be  calculated. 

Table  V.  gives  the  safe  offset  for  masonry  footing  courses,  in  terms 
of  the  thickness  of  the  course,  computed  by  a  factor  of  safety  of  10. 

TABLE  V. 


Fig.  30. 


KIND   OF   FOOTING. 

R.  IN 
LBS.  PBR 
SQ.     IN.* 

OFFSBT   FOR   A   PRESSURE,    IN  TONS    PER  SQUARE 
FOOT  ON  THE   BOTTOM   OF  THE   COURSE,   OF 

0.5 

i 

' 

3 

5 

10 

T~ 

:i 

•3 
1.9 

•5 

Bluestone  flagging  

3,700 

3-6 

9.6 

8 

i-5 

1 

•a 

Limestone  

1,500 
1.200 
5.400 

1,200 

ISO 
80 

1:1 

l'°6 
0.8 

0.6 

3 

ii 

0.6 
0.4 

•  3 
•3 
•5 
•3 

0.4 
0-3 

i.i 

I.O 
I.O 

Slate    

1  i  Portland  

Concrete  \  a  sand  .  .   
|  3  pebbles  

j  i  Rosendale 

Concrete  \  a  sand     

|3pebbles  

'Modulus  of  Rupture,  values  given  by  Prof.  Baker  in  "  Treatise  on  Masonry  Construction.' 


MASONRY  FOOTINGS.  65 

It  should  be  borne  in  mind  that  as  each  footing  course  transmits 
the  entire  weight  of  the  wall  and  its  load,  the  pressure  will  be  greater 
per  square  foot  on  the  upper  courses,  and  the  offsets  should  be  made 
proportionately  less. 

71.  Example. — A  4-foot  footing  course  of  limestone  transmits  a 
load  of  12  tons  per  lineal  foot  or  3  tons  per  square  foot ;  the  thick- 
ness of  the  course  is  10  inches.  What  should  be  the  width  of  the 
course  above  ? 

Answer. — From  the  table  under  the  column  headed  3  we  find  the 
projection  to  be  i.i  times  the  thickness,  or  in  this  case  n  inches. 
As  we  would  have  the  same  projection  each  side  of  the  wall,  the 
stone  above  may  be  22  inches  less  in  width,  or  2  feet  2  inches  wide. 
Except  in  cases  where  it  is  necessary  to  obtain  very  wide  footings  it 


fig.  31. 


Fig.  3*. 


Fig.  33. 


Fig.  34- 


is  better  not  to  make  the  offsets  more  than  6  or  8  inches,  and  in  the 
case  above  it  would  be  better  to  make  the  upper  footing  course  3  feet 
wide.  Most  building  ordinances  require  the  projection  of  the  footings 
beyond  the  foundation  wall  to  be  at  least  6  inches  on  each  side. 

72.  Brick  Footing's. — On  sandy  soils  brick  foundations  and 
footings  may  be  used  when  good  stone  cannot  be  cheaply  obtained. 
In  Denver,  Col.,  where  the  soil  is  a  mixture  of  sand  and  clay,  very 
dry  and  unaffected  by  frost,  brick  foundations  have  been  found  to 
answer  the  purpose  fully  as  well  as  stone  for  two  and  three-story 
buildings. 


BUILDING  CONSTRUCTION. 


In  building  brick  footings,  the  principal  point  to  be  attended  to  is 
to  keep  the  back  joints  as  far  as  possible  from  the  face  of  the  work, 
and  in  ordinary  cases  the  best  plan  is  to  lay  the  footings  in  single 
courses  ;  the  outside  of  the  work  being  laid  all  headers,  and  no  course 
projecting  more  than  one-quarter  brick  beyond  the  one  above  it, 
except  in  the  case  of  unloaded  p-inch  walls.  The  bottom  course 
should  in  all  cases  be  a  double  one.  Figs.  31-34  show  the  proper 
arrangement  of  the  brick  in  walls  from  one  to  three  bricks  in  thick- 
ness. If  the  ground  is  soft  and  compressible,  or  the  wall  heavily 
loaded,  the  footings  should  be  made  wider,  as  shown  in  Fig.  35.  For 
brick  footings  under  high  walls,  or  walls  that  are  very  heavily  loaded, 
each  projecting  course  should  be  made  double,  the  heading  course 
above  and  the  stretching  course  below. 

The  bricks  used  for  footings  should  be  the  hardest  and  soundest 
that  can  be  obtained,  and  should  be  laid  in  cement  or  hydraulic  lime 

mortar,  either  grouted  or  thor- 
oughly slushed  up,  so  that  every 
joint  shall  be  entirely  filled  with 
mortar.  The  writer  favors  grout- 
ing brick  walls,  that  is,  using  thin 
mortar  for  filling  the  inside  joints, 
as  he  has  always  found  it  to  give 
very  satisfactory  results. 

The  bottom  course  of  the  foot- 
ing should  always  be  laid  in  a  bed 
of  mortar  spread  on  the  bottom  of  the  trench,  after  the  latter  has 
been  carefully  leveled.  All  bricks  laid  in  warm  or  dry  weather  should 
be  thoroughly  wet  before  laying,  for,  if  laid  dry,  the  bricks  will  rob 
the  mortar  of  a  large  percentage  of  the  moisture  it  contains,  greatly 
weakening  the  adhesion  and  strength  of  the  mortar. 

Too  much  care  cannot  be  bestowed  upon  the  footing  courses  of 
any  building,  as  upon  them  depends  much  of  the  stability  of  the 
work.  If  the  bottom  courses  are  not  solidly  bedded,  if  any  seams  or 
vacuities  are  left  in  the  beds  of  the  masonry,  or  if  the  materials  them- 
selves are  unsound,  the  effects  of  such  carelessness  are  sure  to  show 
themselves  sooner  or  later,  and  almost  always  when  they  cannot  be 
well  remedied.  Nothing  is  more  apt  to  injure  the  reputation  of  a 
young  architect  than  to  have  a  building  constructed  under  his  direc- 
tion settle  and  crack,  and  he  should  see  personally  that  no  part  of 
the  foundation  work  is  in  any  way  slighted. 


. 

r 

1 

1 

i       i 

1 

i      i 

1             1 

i      i 

1               1 

, 

i      i 

1 

Fig.  35. 

MASONRY  FOOTINGS. 


67 


73.  Inverted  Arches. — Inverted  arches  are  sometimes  built 
under  and  between  the  bases  of  piers,  as  shown  in  Fig.  36,  with  the 
idea  of  distributing  the  weight  of  the  piers  over  the  whole  length  of 
the  footings.  This  method  is  objectionable— first,  because  it  is 
nearly  impossible  to  prevent  the  end  piers  of  a  series  from  being 
pushed  outward  by  the  thrust  of  the  arch,  as  shown  by  the  dotted  line, 
and  second,  it  is  generally  impossible  with  inverted  arches  to  make 
the  areas  of  the  different  parts  of  the  foundation  proportional  to  the 
load  to  be  supported.  It  is  much  better  to  build  the  piers  with  sep- 
arate footings,  projecting  equally  on  all  four  sides  of  the  pier  and  pro- 
portioned to  the  load  supported  by  the  piers.  The  intermediate  wall 
may  either  be  supported  by  steel  beams  or  arches,  as  preferred. 

In  some  instances,  however,  when  building  on  comparatively  soft 
soils,  and  where  it  is  impracticable  to  use  spread  footings,  inverted 


Fig.  36. 

arches  may  be  advantageously  used,  especially  when  it  is  necessary 
to  reduce  the  height  of  the  footing  to  a  minimum. 

If  it  is  decided  to  use  inverted  arches,  the  foundation  bed  should 
be  leveled  and  a  footing  built  over  the  whole  bed  to  a  depth  of  at 
least  12  to  1 8  inches  below  the  bottom  of  the  arch.  Concrete  is 
much  the  best  material  for  this  footing,  although  brick  or  stone  may 
be  used  if  found  more  economical.  The  upper  surface  of  the  foot- 
ing should  be  accurately  formed  to  receive  the  arch.  The  arch 
should  be  built  of  hard  brick,  laid  in  cement  mortar,  and  generally 
in  separate  rings  or  rowlocks,  and  should  abut  against  stone  or  con- 
crete skewbacks,  as  shown  in  Fig.  37. 

It  is  better  to  build  the  arches  before  putting  in  the  skewbacks, 
and  for  the  latter  i  to  6  Portland  cement  concrete  possesses  special 


68 


BUILDING  CONSTRUCTION. 


advantages,  as  the  concrete  can  be  deposited  between  the  ends  of  the 
arches  and  rammed  evenly  and  simultaneously,  thus  giving  a  solid 
and  uniform  bearing  against  the  ends  of  the  arches,  tending  to  pre- 
vent unequal  settlement  and  cracking. 

74.  Above  the  concrete  skewback  a  solid  block  of  stone  should  be 
placed  if  it  can  be  readily  obtained.  The  thickness  of  the  arch  ring 
should  be  at  least  12  inches,  and  heavy  iron  plates  or  washers  should 
be  set  in  the  middle  of  the  concrete  skewbacks  and  connected  with 
iron  or  steel  rods,  to  take  up  the  thrust  of  the  end  arches.  The 


Stone, Brick,  orConcrete 


Fig.  37- 

"  rise"  of  the  arch,  or  distance  R,  Fig.  37,  should  be  equal  to  from 
one-fourth  to  one-sixth  of  the  span.  The  sectional  area  of  the  arch 
should  equal  the  result  obtained  by  the  following  formula: 

Section  of  arch  in  sq.  inches  =  Total  load  on  arch  (in  Ibs.)  X  span 
and  the  area  of  the  tie  rods  should  equal 


Total  load  on  arch  (in  Ibs  )  X  span  , 

~—  for  wrought  i 


and 


Total  load  on  arch  X  span  ,  . 

8X^X1050  ' 


the  span  being  measured  in  feet,  and  the  distance  R  in  inches. 

The  load  on  the  arch  will  be  equal  to  the  span  multiplied  by  the 
pressure  per  tinea!  foot  imposed  on  the  soil.  The  latter  will  be 
obtained  by  dividing  the  load  on  the  piers  by  the  distance  between 
centres  of  piers. 

75.  Example.— It  is  desired  to  use  inverted  arches  between  the 
piers  of  a  three-story  building,  resting  on  a  soil  whose  bearing  power 


FOUNDATION  WALLS.  69 

cannot  be  safely  estimated  at  over  3,000  pounds  per  square  foo 
The  piers  are  of  stone,  4  feet  long,  22  inches  thick,  and  14  feet  apart 
from  centres.     Each  pier  supports  a  total  load  of  98,000  pounds. 
What  should  be  the  sectional  area  of  the  arch,  and  of  the  rods  in  end 
spans  ? 

Answer. — The  span  of  the  arch  will  be  10  feet,  and  the  distance 
R  about  one-fifth  of  10  feet,  or  24  inches.  The  load  per  lineal  foot 
on  the  soil  will  equal  98,000-^14,  or  7,000  pounds.  The  footing 
\mder  the  arch  must  therefore  be  2  feet  4  inches  wide  to  reduce  the 
pressure  to  3,000  pounds  per  square  foot.  The  width  of  the  arch 
itself  we  will  make  22  inches,  or  two  and  one-half  bricks.  The  total 
load  on  the  arch  will  equal  10X7,000,  or  70,000  pounds 

The  sectional  area  of  the  arch  must  therefore  equal 

70000X1°  or  354  square  inches. 
8X24X10 

As  the  width  is   22  inches,  the  depth  must  equal  354-7-22,  or  16 
inches,  which  will  require  four  rowlocks  or  rings. 

The  sectional  area  of  the  ties  must  equal,  for  wrought  iron, 

70000X10  or  4.3  square  inches. 
8X24X850 

In  this  case  it  will  be  better  to  use  two  rods  of  2.15  square  inches  in 
area,  or  say  two  i^-inch  rods. 

All  cast  iron  work  in  the  foundation  should  be  coated  with  hot 
asphalt,  and  the  rods  should  be  dipped  in  linseed  oil  while  new  and 
hot  and  afterward  painted  one  heavy  coat  of  oxide  of  iron  or  red 
lead  paint. 

FOUNDATION  WALLS. 

76.  This  term  is  generally  applied  to  those  walls  which  are  below 
the  surface  of  the  ground,  and  which  support  the  superstructure. 
Walls  whose  chief  office  is  to  withhold  a  bank  of  earth,  such  as 
around  areas,  are  called  retaining  walls. 

Foundation  walls  may  be  built  of  brick,  stone  or  concrete,  the  for- 
mer being  the  most  common.  Brick  walls  for  foundations  are  only 
suitable  in  very  dry  soils,  or  in  the  case  of  party  walls,  where  there 
is  a  cellar  or  basement  each  side  of  them. 

As  the  method  of  building  brick  foundations  is  the  same  as  for  any 
brick  wall,  it  will  not  be  described  here,  but  taken  up  in  the  chapter 
on  Brickwork.  For  concrete  walls  see  Chapter  XII. 


7o  BUILDING  CONSTRUCTION. 

77.  Stone  Watts.— The  principal  points  to  be  watched  in  building 
a  stone  foundation  wall  are  the  character  of  the  stone  and  mortar, 
bonding,  filling  of  voids  and  pointing. 

The  best  stones  for  foundations  are  granites,  compact  sandstones, 
slates  and  blue  shale.  The  less  porous  the  stone  the  better  it  will 
stand  the  dampness  to  which  it  must  be  subjected.  As  a  rule  lami- 
nated stones  make  the  best  wall,  as  they  split  easily  and  give  flat  and 
parallel  beds.  If  the  only  stone  to  be  had  is  boulders  or  field  stone, 
they  should  be  split  so  as  to  form  good  bed  joints.  Cobble  or  round 
stones  should  never  be  used  for  building  foundation  walls,  and  for  all 
buildings  exceeding  three  stones  in  height,  block  stone  or  the  best 
qualities  of  laminated  stone  should  be  used. 

The  mortar  for  foundation  walls  below  the  grade  line  should  be 
made  either  of  natural  cement,  or  hydraulic  lime,  and  coarse  sand  ; 
above  grade  good  common  lime,  or  lime  and  cement,  may  be  used. 

The  usual  practice  in  building  foundations  is  to  use  the  stone  just 
as  it  is  blasted  from  the  quarry,  or,  if  the  building  is  built  on  a  ledge, 
from  the  foundation  itself,  the  stone  receiving  no  preparation  other 
than  breaking  it  up  with  a  sledge  hammer,  and  squaring  one  edge 
for  the  face.  Too  great  irregularity  and  unevenness  is  overcome  by 
a  sparing  use  of  the  stone  hammer  and  by  varying  the  thickness  of 
the  mortar  joint  in  which  the  stones  are  bedded.  The  strength  of 
the  wall,  therefore,  depends  largely  upon  the  quality  of  the  mortar 
used. 

The  wall  should  be  leveled  off  about  every  2  feet,  so  as  to  form 
irregular  courses,  and  the  horizontal  joints  should  be  kept  as  nearly 
level  as  possible. 

When  block  stone  is  used  the  stones  are  generally  from  18  inches 
to  2  feet  thick  and  the  full  width  of  the  wall.  They  are  commonly 
roughly  squared  with  the  hammer,  and  but  little  mortar  is  used  in  the 
wall.  Only  in  a  few  localities,  however,  are  such  stones  obtainable 
at  a  price  that  will  permit  of  their  use,  so  that  as  a  rule  stone  split 
from  a  ledge  and  called  "  rubble"  is  the  *  material  with  which  the 
architect  will  have  to  deal. 

78.  Bonding. — Aside  from  the  quality  of  the  stone  and  mortar,  the 
strength  of  a  rubble  wall  depends  upon  the  manner  in  which  it  is 
bonded  or  tied  together  by   lapping  the   stones   over  each  other. 
About  every  4  or  5  feet  in  each  course  a  bond  stone  should  be  used ; 
that  is,  a  stone  that  will  go  entirely  through  the  wall,  and,  by  its  fric- 
tion on  the  stones  below,  hold  them  in  place.     A  stone  that  goes 
three-fourths  of  the  way  through  the  wall  is  called  a  three-quarter 


FO  UN  DA  TION  WALLS.  7 1 

bond.  It  is  usually  customary  to  specify  that  there  shall  be  at  least  one 
through  stone  in  every  5  or  10  square  feet  of  the  wall,  depending  upon 
the  character  of  the  stone  and  nature  of  the  building.  Fig.  38  shows 
a  portion  of  wall  built  of  square  or  laminated  stone,  with  through 
bond  stone,  B  J3,  and  three-quarter  bond  stones  at  A  A.  A  good 
three-quarter  bond  is  nearly  equal  in  strength  to  a  through  bond,  and 
when  the  character  of  the  stone  will  permit  of  the  wall  being  built 
largely  of  flat  stone  extending  two-thirds  of  the  way  through  the  wall, 
it  will  not  be  necessary  to  use  more  than  one  through  stone  to  every 


Fig.  38. 

10  square  feet  of  wall.  No  stone  should  be  built  into  the  face  of  a 
wall  with  a  less  depth  than  6  inches,  although  stone  masons  will  often 
set  a  stone  on  edge,  so  as  to  make  a  good  face  and  give  the  appear- 
ance of  a  large  stone,  when  it  may  be  only  3  inches  thick.  All  kinds 
of  stones  should  always  be  laid  so  that  their  natural  bed,  or  splitting 
surface,  will  be  horizontal.  It  is  also  important  that.the  stones  shall 
break  joint  longitudinally,  as  in  Fig.  38,  and  not  have  several  vertical 
joints  over  each  other,  as  at  A  A,  Fig.  39,  The  angles  of  the  foun- 
dation should  be  built  up  of  long  stone,  laid  alternately  header  and 
stretcher,  as  shown  in  Fig.  40.  The  largest  and  best  stone  should 
always  be  put  in  the  corners,  as  these  are  usually  the  weakest  part  of 
the  wall. 


BUILDING  CONSTRUCTION. 


79.  Filling  of  Voids. — All  stones,  large  and  small,  should  be 
solidly  bedded  in  mortar,  and  all  chinks  or  interstices  between  the 
large  stones  should  be  partially  filled  with  mortar  and  then  with 
small  pieces  of  stone,  or  spalls,  driven  into  the  mortar  with  the 

trowel,  and  then  smoothed  off 
on  top  again  with  mortar. 

Many  masons  are  apt  to 
build  the  two  faces  of  the  wall 
with  long,  narrow  stones  and 
fill  in  between  with  dry  stone, 
throwing  a  little  mortar  on  top 
to  make  it  look  well. 

A  horizontal  section  through 
such  a  wall  would  appear  as 
shown  in  Fig.  41.  Such  a  wall 
would  require  but  little  loading 
to  cause  the  outside  faces  to 
bulge,  owing  to  the  lack  of 
strength  in  the  middle  portion. 
The  way  in  which  a  wall  of  irregular  shaped  stones  should  be  built 
to  get  the  most  strength  is  shown  in  Fig.  42. 

Such  a  wall  requires  no  more  stone  than   the  other,  but  requires 


Fig-  39- 


Fig.  4* 


more  lifting  and  a  little  more  use  of  the  hammer,  and  these  appear 
to  be  the  real  reasons  why  better  work  is  not  more  generally  done 

80.  Window  Openings.— If  there  should  be  a  window  or  door 
opening  m  the  foundation  wall,  as  in  Fig.  43,  the  stones  just  below 


FO  UNDA  TION  WALLS. 


73 


the  opening  should  be  laid  so  as  to  spread  the  weight  of  the  wall  under 
the  opening,  as  shown  by  the  stones  ABC.  If  there  is  to  be  any 
great  weight  come  upon  the  foundation  it  will  be  better  not  to  build 
the  window  sills  into  the  wall,  but  to  make  their  length  just  equal  to 

the  width  of  the  opening, 
or  slip  sills,  as  they  are 
called,  then  there  will  be 
no  danger  of  their  break- 
ing by  uneven  settlement 
of  the  wall. 

Occasionally  part  of  the 
foundation  wall  of  a  build- 
ing goes  down  much  lower 
than  the  adjoining  portion, 
and,  as  there  is  almost 
always  a  slight  settlement 

in  the  joints  of  the  wall,  unless  laid  in  cement  the  deeper  wall  will 
naturally  settle  more  than  the  other,  and  thus  cause  a  slight  crack. 
This  can  be  avoided  by  building  the  deeper  wall  of  larger  stone,  so 


Fig.  41. 


Fig.  43- 


that  there  will  be  no  more  joints  than  in  the  other  wall,  or  by  mak- 
ing thin  joints  and  using  cement  mortar. 

81.  Thickness  of  Foundation  Walls. — The  thickness  of  the 
foundation  wall  is  usually  governed  by  that  of  the  wall  above,  and 
also  by  the  depth  of  the  wall. 


74 


B  UILDING  CONS  TR  UCTION. 


Nearly  all  building  regulations  require  that  the  thickness  of  the 
foundation  wall,  to  the  depth  of  12  feet  below  the  grade  line,  shall 
be  4  inches  greater  than  the  wall  above  for  brick  and  8  inches 
for  stone,  and  for  every  additional  10  feet,  or  part  thereof  deeper, 
the  thickness  shall  be  increased  4  inches.  In  all  large  cities  the 
thickness  of  the  walls  is  controlled  by  law.  For  buildings  where  the 
thickness  is  not  so  governed  the  following  table  will  serve  as  a  fair 
guide: 

TABLE  VI.— THICKNESS  FOR  FOUNDATION  WALLS. 


HEIGHT   OF  BUILDING.  ' 

DWELLINGS,    HOTELS, 
ETC. 

WAREHOUSES. 

BRICK. 

STONE. 

BRICK. 

STONE. 

Ins. 
12  or  16 
16 

20 

24 
24 

Ins. 
20 

20 

24 

28 

28 

Ins. 
16 

20 
24 
24 

28 

Ins. 

20 

24 

28 
28 
32 

S'x  stories 

Only  block  stone,  or  first-class  rubble,  with  flat  beds,  should  be 
used  in  foundations  for  buildings  exceeding  three  stories  in  height. 
The  footings  should  be  at  least  12  inches  wider  than  the  width  of  the 
walls.  (See  Section  66.) 

In  heavy  clay  soils  it  is  a  good  idea  to  batter  the  walls  on  the  out- 
side, making  the  wall  from  6  inches  to  a  foot  thicker  at  the  bottom 
that  it  is  at  the  top,  and  plastering  the  outside  with  cement.  (See 
Fig.  3,  Section  10.) 

RETAINING  WALLS. 

82.  A  retaining  wall  is  one  that  is  built  to  hold  up  a  bank  of 
earth,  which  is  afterward  deposited  behind  it.  Retaining  walls  dif- 
fer from  foundation  walls,  in  that  the  latter  support  a  superstructure 
whose  weight  is  generally  sufficient  to  overcome  the  thrust  of  the 
earth  against  the  wall.  A  retaining  wall,  on  the  other  hand,  depends 
upon  its  own  stability  to  resist  the  earth  pressure. 

True  retaining  walls  are  seldom  designed  by  the  architect,  as  the 
only  place  for  which  he  would  be  likely  to  plan  such  walls  is  for  the 
support  of  terraces,  etc. 

Area  walls,  it  is  true,  generally  serve  as  retaining  walls,  but  as  they 
are  usually  braced  by  arches  or  cross  walls  from  the  building  wall, 
they  do  not  require  the  same  thickness  as  a  retaining  wall  proper. 
Several  theoretical  formulae  have  been  evolved  by  writers  on  engi- 
neering subjects  for  computing  the  necessary  thickness  and  most 


RETAINING  WALLS. 


75 


economical  section  of  retaining  walls,  but  so  many  variable  condi- 
tions enter  into  the  designing  of  such  walls,  such  as  the  character  and 
cohesion  of  the  soil,  the  amount  the  bank  has  been  disturbed,  the 
manner  in  which  the  material  is  filled  in  against  the  wall,  etc.,  that 
little  confidence  is  placed  in  these  theoretical  formulae  by  practical 
engineers,  and  they  appear  to  be  guided  more  by  empirical  rules, 
derived  from  experience. 

The  cross  section  that  appears  to  be  most  generally  approved  for 

retaining  walls,  particularly  in  engineering  work,  is  shown  in  Fig.  44. 

The  wajl  may  either  be  built  plumb,  as  shown,  or  inclined  toward 

the  bank.     The  latter  method  is  generally  considered  as  securing 

greater   stability,  although   it  is 

f  open  to  the   objection  that  the 

water  which  runs  down  the  face 

/  of  the  wall  is  apt  to  penetrate 

into  the  inclined  joints. 

Retaining  walls  should  be 
built  only  of  good  hard  split  or 
block  stone,*laid  in  cement  mor- 
tar and  carefully  bonded,  to  pre- 
vent the  stones  from  sliding  on 
the  bed  joints. 

The  thickness  of  the  wall  at 
the  top  should  be  not  less  than 
1 8  inches,  and  the  thickness,  a, 
just  above  each  step  should  be 
from  one-third  to  two-fifths  of 
the  height  from  the  top  of  the 
wall  to  that  point. 

If  the  earth  is  banked  above 
the  top  of  the  wall,  as  shown  by  the  dotted  line,  Fig.  44,  the  thick- 
ness of  the  wall  should  be  increased.  A  thickness  equal  to  one-half 
of  the  height  will  generally  answer  for  a  height  of  embankment  equal 
to  one-third  that  of  the  wall. 

The  outer  face  of  the  wall  is  generally  battered,  or  sloped  outward, 
about  i  inch  to  the  foot. 

Stepping  the  wall  on  the  back  increases  the  stability  by  bonding 
the  wall  into  the  material  behind  and  having  its  weight  increased  by 
the  weight  of  the  soil  resting  upon  the  steps. 

If  built  upon  ground  that  is  affected  by  frost  or  surface  water,  the 

*  Or  Portland  cement  concrete  with  twisted  iron  bars. 


Fig.  44- 


BUILDING  CONSTRUCTION. 


footings  should  be  carried  sufficiently  below  the  surface  of  the  ground 
at  the  base  of  the  wall  to  insure  against  heaving  or  settling. 

If  the  ground  back  of  the  wall  slopes  toward  the  wall  a  cement 
gutter  should  be  formed  behind  the  coping  and  connected  with  a 
drain  pipe  to  carry  off  the  surface  water.  The  back  of  the  wall  and 
tops  of  steps  should  be  plastered  with  cement  to  the  depth  of  at  least 

3  or  4  feet. 

AREA  WALLS. 

83.  Areas  are  often  excavated  outside  the  foundation  walls  of 
buildings  to  give  light  or  access  to  the  basement,  and  require  to  be 
surrounded  by  a  wall  to  retain  the  bank  and  present  a  neat  appearance. 

Such  walls  should  be  built  of  stone,  as  a  stone  wall  offers  greater 
resistance,  when  the  mortar  is  green,  to  sliding  on  the  bed  joints  than 
a  brick  wall. 

In  making  the  excavation  the  bank  should  be  disturbed  as  little  as 
possible,  and  in  filling  against  the  wall  the  soil  should  be  deposited 
in  layers  and  well  tamped,  and  not 
dumped  carelessly  behind  the  wall.  The 
filling  should  also  be  delayed  until  the 
mortar  has  had  time  to  harden,  or  else 
the  wall  should  be  well  braced. 

Area  walls  are  commonly  built  in  the 
same  manner  as  foundation  walls  and  of 
a  uniform  thickness,  generally  about  20 
inches  for  a  depth  of  7  feet.  If  more 
than  7  feet  in  height  the  wall  should  have 
a  batter  on  the  area  side  and  should  be 

increased  in  thickness  at  the  bottom,  so  that  the  average  thickness  of 
the  wall  will  be  at  least  one-third  of  the  height,  unless  the  wall  is 
braced  by  arches,  buttresses  or  cross  walls. 

Area  walls  sustaining  a  street  or  alley  should  be  made  thicker  than 
those  in  an  open  lot. 

When  an  area  wall  is  more  than  10  feet  long  it  is  generally  prac- 
ticable to  brace  it  from  the  basement  wall  by  arches  thrown  across 
from  one  wall  to  the  other,  as  shown  in  Fig.  45.  When  this  cannot 
be  done  the  wall  should  be  stiffened  by  buttresses  about  every  10  feet. 

VAULT  WALLS. 

84.  In  large  cities  it  is  customary  to  utilize  the  space  under  the 
sidewalk  for  storage  or  other  purposes.     This  necessitates  a  wall  at 
the  curb  line  to  sustain  the  street  and  also  the  weight  of  the  sidewalk. 


Fig.  45- 


AREA  AND   VAULT  WALLS. 


77 


Where  practicable,  the  space  should  be  divided  by  partition  walls 
about  every  10  feet,  and  when  this  is  done  the  outer  wall  may  be 
advantageously  built  of  hard  brick  in  the  form  of  arches,  as  shown  in 
Fig.  46. 

The  thickness  of  the  arch  should  be  at  least  16  inches  for  a  depthi 
of  9  feet,  and  the  "  rise  "  of  the  arch  one-sixth  of  the  span. 

If  partitions  are  not  practicable,  each  sidewalk  beam  may  be  sup- 
ported by  a  heavy  I-beam  column,  with  either  flat  or  segmental  arches 
between,  as  shown  in  Fig.  47. 

This  latter  method  is  more  economical  of  space  than  any  other, 
and  where  steel  is  cheap  is  about  as  economical  in  cost. 

SUPERINTENDENCE  OF  FOUNDATION  WORK. 
85.  The   first  work   on  the   foundations  will  be  putting   in   the 
footings. 


Fig.  46.  Fig.  47. 

If  the  footings  are  of  concrete,  an  inspector  should  be  put  on  the 
work  to  stay  during  the  entire  working  hours,  and  see  that  every  batch 
of  concrete  is  mixed  in  exactly  the  proportion  specified,  and  that  the 
aggregates  are  broken  to  the  proper  size  and  the  cement  all  of  the 
same  brand  and  in  good  condition.  There  is  no  building  operation 
that  can  be  more  easily  "skimped"  without  detection  than  the 
making  of  concrete,  and  the  only  way  by  which  the  architect  can  be 
sure  that  his  specifications  have  been  strictly  followed  is  by  keeping: 
a  reliable  representative  constantly  on  the  ground.  The  inspector 
should  also  see  that  the  concrete  is  put  in  to  the  full  thickness  shown 
on  the  drawings,  and  that  it  is  leveled  and  tamped  every  6  inches, 
in  depth. 

Should  water  be  encountered  in  the  trenches,  it  should  be  collected', 
in  a  shallow  hole  and  removed  by  a  pump  or  drain,  as  explained  .ni 


78  BUILDING  CONSTRUCTION. 

Section  31.  Very  often,  when  the  foundation  rests  on  the  top  of  a 
ledge,  underlying  gravel  or  clay,  running  water  will  be  encountered  in 
the  trenches  in  too  great  a  volume  to  be  readily  removed.  In  such 
a  case,  the  flow  of  the  water  should  be  intercepted  by  a  drain  and 
cesspool,  and  a  tight  drain  carried  from  the  latter  to  a  sewer  or  to  a 
dry  well  below  the  foundation  of  the  building. 

Concrete  footings  for  piers  not  more  than  4  or  5  feet  square 
may  be  built,  where  there  is  running  water,  by  making  large  bags  of 
oiled  cotton  and  sinking  them  in  the  pit,  filling  the  concrete  into 
them  immediately.  The  water  will  probably  rise  around  the  bag,  but 
if  the  latter  keeps  the  water  away  from  the  concrete  until  the  cement 
has  had  time  to  set,  it  will  have  answered  its  purpose.  Water  does 
not  injure  concrete,  or  mortar  made  of  cement,  after  it  has  begun  to 
harden,  but  if  freshly-mixed  concrete  is  thrown  into  water  the  water 
separates  the  cement  from  the  sand  and  aggregates,  the  cement  mixing 
with  the  water  and  floating  away,  while  the  sand  and  stone  drops  to 
the  bottom.  For  this  reason  concrete  should  never  be  thrown  into 
trenches  containing  water. 

86.  If  the  footings  are  of  stone  the  presence  of  water  does  not  do 
as  much  harm,  provided  the  water  can  be  drained  so  as  not  to  attain 
a  greater  depth  than  3  or  4  inches.  Sometimes  the  bottom  of 
the  wall  is  used  as  a  drain  for  collecting  the  seepage  water,  and  the 
trench  is  partially  filled  with  stones  laid  without  mortar,  as  explained 
in  Section  10. 

For  heavy  buildings,  however,  the  footings  should  be  solidly  bedded 
in  cement  mortar  when  the  trenches  are  reasonably  dry,  and  when 
this  is  not  the  case,  in  sand  or  fine  gravel.  An  irregular  footing 
stone  can  often  be  bedded  more  solidly  by  piling  fine  sand  around 
it  and  then  washing  the  sand  under  the  stone  with  water,  than  it  can 
in  cement  mortar.  The  former  method,  however,  takes  more  time, 
and  would  seldom  be  employed  where  mortar  could  be  used  as  well. 

As  stated  in  Section  72,  too  much  care  cannot  be  bestowed  upon 
the  footing  courses  of  any  building,  and  there  is  no  portion  of  the 
building  that  needs  closer  inspection  than  the  footings  and  foundation. 

Before  the  masons  commence  actual  operations  the  architect 
should  inspect  all  materials  that  have  been  delivered,  to  see  that  they 
are  of  the  kind  and  quality  specified. 

The  mortar,  together  with  the  sand,  cement  or  lime,  should  be  par- 
ticularly examined,  to  see  that  the  mortar  has  the  proper  proportions 
of  cement  or  lime,  and  is  well  worked;  that  the  cement  or  lime  is 
fresh  and  all  of  the  kind  or  brand  specified;  and  that  the  sand  is 


FOUNDATION  WALLS- SUPERINTENDENCE,    79 

clean  and  sharp.  The  building  of  the  foundation  wall  should  also 
be  carefully  watched  to  see  that  the  wall  is  well  tied  together  with 
plenty  of  three-quarter  and  through  bond  stones,  and  that  the  inside 
is  solidly  filled  with  stone  and  mortar. 

The  superintendent  must  also  examine  the  wall  occasionally  to  see 
that  it  is  built  straight  and  plumb,  and  that  the  general  bed  of  the 
courses  is  horizontal. 

When  inspecting  stonework  already  built,  but  which  has  not  had 
time  for  the  mortar  to  harden,  a  light  steel  rod,  about  -fa  inch  in  di- 
ameter and  4  or  5  feet  long,  will  be  found  useful.  If  the  rod  can  be 
pushed  down  into  the  centre  of  the  wall  more  than  18  inches  or  2 
feet  in  any  place  it  shows  that  the  stones  have  not  been  lapped  over 
each  other,  and  if  this  can  be  done  in  several  places  the  inspector 
should  order  the  wall  taken  down  and  rebuilt.  The  rod  will  also 
indicate  to  a  considerable  extent  whether  or  not  the  stones  in  the 
centre  of  the  wall  have  been  well  bedded,  as  if  they  have  not  they 
will  rock  or  tip  when  struck  with  the  rod. 

The  inspection  of  a  foundation  wall  cannot  be  too  thorough,  as  there 
is  nothing  that  causes  an  architect  so  much  trouble  as  to  have  settle- 
ments in  the  foundations  of  his  buildings. 

87.  Filling  in. — In  buildings  where  the  cellar  floor  is  6  feet  or 
more  below  the  ground  level  the  trenches  behind  the  walls  should  not 
be  filled  in  until  the  floor  joists  are  on  and  the  wall  built  6  feet  or 
more  above  them,  or  until  the  walls  are  solidly  braced  with  heavy 
timbers,  otherwise  the  wall  may  be  sprung  by  the  pressure  of  loose 
dirt.  In  heavy  clay  soils  it  is  a  good  idea  to  fill  in  back  of  the  wall 
with  coarse  gravel,  stone  spalls  and  sand,  as  frost  will  not  "  heave  " 
them  as  it  does  clay. 

Holes  for  Soil  and  Supply  Pipes. — In  thick  walls,  and  when 
built  of  heavy  stone,  the  architect  should  locate  the  position  of  the 
soil  and  supply  pipes,  and  see  that  openings  are  left  in  the  proper 
places  for  the  pipes  to  pass  through  the  wall. 


8o 


BUILDING  CONSTRUCTION. 


DAMPNESS  IN  CELLAR  WALLS. 

88.  In  many  localities  it  is  necessary  to  guard  against  dampness  in 
cellar  walls,  particularly  in  buildings  where  the  basement  is  used  for 
living  rooms  or  for  storage.  There  are  several  devices  for  pre- 
venting moisture  from  entering  the  walls,  one  class  being  in  the  nature 
of  applications  to  the  outside  of  the  wall  and  the  other  being  con-, 
structive  devices. 

Where  only  surface  water  is  to  be  provided  against,  and  the 
ground  is  not  generally  saturated  with  water,  coating  the  outside  of 
the  wall  with  asphalt  or  Portland  cement  will,  in  most  cases,  prove  a 
preventative  against  dampness. 

Asphalt,  applied  to  the  outside  of  the  wall  while  boiling  hot,  is 
generally  considered  as  the  most  lasting  and  durable  of  all  coatings. 
To  insure  perfect  protection,  the  wall  should  have  been  built  as  care- 
fully as  (  possible,  the  joints  well 
pointed  and  the  whole  allowed  to 
get  dry  before  the  coating  is 
applied. 

The  asphalt  should  be  applied 
in  two  or  more  coats  and  carried 
down  to  the  bottom  of  the  foot- 
ings. 

If  the  soil  is  wet  and  generally 
saturated  with  water,  moisture  is 
apt  to  rise  in  the  wall  by  absorp- 
tion from  the  bottom.  To  prevent 
this,  two  or  three  thicknesses  of 
asphaltic  felt,  laid  in  hot  asphalt, 
should  be  bedded  on  top  of.  the 
footings,  just  below  the  basement 
floor,  as  shown  by  the  heavy  line, 
Fig.  48. 

Portland  cement  may  be  used  in  place  of  asphalt  if  the  ground  is 
not  exceeding  damp,  but  if  it  is  often  saturated  with  water  asphalt 
should  be  used.  The  objections  to  Portland  cement  are  that  it  is 
easily  fractured  by  any  settlement  of  the  walls,  and  being  to  some 
degree  porous,  suffers  from  the  action  of  frost. 

Common  coal  tar  is  also  often  used  for  coating  cellar  walls;  it 
answers  the  purpose  very  well  for  a  time,  but  gradually  becomes  brit- 
tle and  crumbles  away. 


DAMPNESS  IN  FOUNDATION  WALLS,  81 

89.  Of  the  constructive  devices,  the  simplest  is  to  make  the  exca- 
vation about  2  feet  larger  each  way  than  the  building,  so  that  there 
will  be  about  a  foot  or  10  inches  between  the  bottom  of  the  bank 
and  the  wall,  as  shown  in  Fig.  48.  A  V-shaped  tile  drain  should  be 
placed  at  the  bottom  of  this  trench  after  the  wall  is  built  and  con- 
nected with  a  horizontal  drain,  carried  some  distance  from  the 
building. 

The  trench  should  then  be  filled  with  cobbles,  coarse  gravel  and 
sand.  If  the  top,  for  a  distance  of  about  2  feet  from  the  building,  is 
covered  with  stone  flagging  or  cement,  it  will  assist  greatly  in  keeping 
the  walls  dry. 

By  draining  the  soil  in  this  way,  and  also  coating  the  wall  with 
asphalt  or  concrete,  a  perfectly  dry  wall  will  in  most  cases  be  insured 

For  greater  protection  of  the  basement  from  dampness,  the  base- 
ment walls  should  be  lined  with  a  4-inch  brick  wall  with  an  air  space 
between  the  main  wall  and  the  lining,  or  an  area  should  be  built  all 
around  the  outside  walls. 

WINDOW  AND  ENTRANCE  AREAS. 

QO.  These  features,  although  not  strictly  a  part  of  the  foundations, 
are  intimately  connected  with  them,  and  are  generally  included  in 
the  same  contract. 

The  thickness  and  bracing  of  area  walls  has  already  been  consid- 
ered (see  Section  83).  The  materials  and  workmanship  of  the  walls 
should  be  the  same  as  in  the  foundation  walls. 

Window  areas  intended  for  light  and  ventilation  should  be  of  ample 
size,  so  as  not  to  obstruct  the  light  more  than  possible. 

For  small  cellar  windows  sunk  not  more  than  2  feet  below  the 
grade  line,  a  semicircular  area  with  a  p-inch  brick  wall  will  give  the 
greatest  durability  for  the  least  cost.  If  the  area  is  3  or  4  feet 
deep,  and  as  many  in  length  and  width,  the  thickness  of  the  wall 
should  not  be  less  than  12  inches  for  brick  and  18  inches  for  stone. 

Area  walls  should  be  coped  with  stone  flagging,  set  in  cement,  the 
edge  of  the  flagging  projecting  i  inch  over  the  face  of  the  wall.  If 
flagging  cannot  be  obtained  without  excessive  expense  the  top  of  the 
wall  should  be  covered  with  i  to  i  Portland  cement  mortar,  about  f 
inch  thick.  Freestones  and  all  porous  stones  are  unsuited  for  area 
or  fence  copings. 

Drainage. — The  bottom  of  the  area  should  be  carried  at  least  6 
inches  below  the  window  sill  and  should  be  formed  of  stone  flagging 
or  of  brick  laid  in  cement.  Beneath  the  bottom  of  the  area  a  small 


82  BUILDING  CONSTRUCTION, 

cesspool  or  sand-trap  (say  8  inches  square)  should  be  built,  which 
should  be  connected  by  a  3-inch  drain  pipe  with  the  main  drain.  A 
cast  iron  strainer  or  drain  plate  should  be  set  over  the  cesspool,  flush 
with  or  a  little  below  the  paving,  so  that  it  can  be  readily  removed 
and  the  cesspool  cleaned.  The  footings  of  the  area  walls  should  be 
started  as  deep  as  the  bottom  of  the  cesspool,  both  being  below  the 
frost  line. 


Fig.  49- 

91.  Entrance  Areas. — All  area  steps,  when  practicable,  should  be 
of  stone,  or  of  stone  and  brick  combined.*  When  the  soil  is  hard  and 
compact  and  not  subject  to  heaving  by  frost,  a  small  set  of  steps  may 
be  economically  built  by  shaping  the  earth  to  the  rake  of  the  steps  and 
building  the  steps  directly  on  the  earth,  laying  two  courses  of  brick,  in 
cement,  for  the  risers,  and  covering  with  2 -inch  stone  treads,  as  shown 


Fig.  5°. 

in  Fig.  49.  All  parts  of  the  steps  should  be  set  in  cement,  and  well 
pointed,  and  the  ends  of  the  treads  should  be  built  into  the  side  walls. 
If  the  area  is  6  feet  or  more  in  depth,  or  if  the  soil  is  sandy  or  a 
wet  clay,  then  the  area  must  be  excavated  beneath  the  steps  and 
entirely  surrounded  by  a  wall.  The  steps  may  be  formed  of  2-inch 
stone  risers  and  treads,  or  of  solid  stone,  the  ends  in  either  case  being 
supported  by  the  side  walls.  If  of  solid  stone  the  front  of  each  step 

*  Or  of  concrete  and  twisted  iron.     (See  page  3691.) 


VAULTS  AND  AREAS.  83 

should  rest  on  the  back  of  the  stone  below  it,  as  shown  at  Ar  Fig. 
50.  If  built  of  treads  and  risers  they  may  be  arranged  either  as  shown 
at  B  or  C.  The  arrangement  shown  at  B  is  the  strongest. 

If  the  steps  are  more  than  5  feet  long  a  bearing  wall  or  iron 
string  should  be  built  under  the  middle  of  the  steps. 

Stone  steps  should  always  be  pitched  forward  about  \  of  an  inch 
in  the  width  of  the  tread. 

In  many  localities  plank  steps,  supported  on  plank  strings,  will  last 
for  a  long  time  if  the  ground  is  excavate^  below  them  and  the  area 
walled  up  all  around,  and  when  they  decay  it  is  a  small  matter  to 
replace  them. 

The  platform  at  the  bottom  of  the  steps  should  be  of  stone  or 
brick,  set  at  least  4  inches  below  the  sill  of  the  door  giving  entrance 
to  the  building,  and  should  be  provided  with  cesspool,  plate  and  drain, 
as  described  in  Section  90. 

All  outside  stone  steps,  fence  coping,  etc.,  should  be  set  on  a  foun- 
dation carried  at  least  2  feet  below  grade,  and  in  localities  affected 
by  frost  below  the  freezing  line. 

92.  Vaults  are  often  built  under  entrance  steps  and  porches,  the 
walls  of  the  vault  forming  the  foundation  for  the  steps  and  platform. 
The  roof  of  the  vault  is  generally  formed  of  a  brick  arch  or  vault,  two 
rowlocks  in  thickness,  with  the  stone  steps  set  in  cement  mortar  on 
top  of  the  arch. 

Vaults  under  sidewalks  may  either  be  arched  over  with  brick,  the 
top  of  the  arch  leveled  off  with  sand,  cinders  or  concrete,  and  the 
sidewalk  laid  thereon,  or  the  sidewalk  itself,  if  of  large  stone  flags, 
may  be  made  to  form  the  roof  of  the  vault.  In  the  latter  case  the 
joints  of  the  stone  slabs  are  closely  fitted  and  often  rebated,  then 
caulked  with  oakum  to  within  about  2  inches  of  the  top  and  the 
remaining  space  filled  with  hot  asphalt  or  asphaltic  mastic.  This  will 
make  a  tight  job  for  a  time,  but  in  the  course  of  two  or  three  years 
the  joints  will  need  to  be  cleaned  out  and  refilled. 

Any  form  of  fireproof  floor  construction  may  also  be  used  for  cov- 
ering sidewalk  vaults  and  a  cement  sidewalk  finished  on  top  of  it. 
This  probably  makes  the  best  walk  and  the  most  durable  construc- 
tion, with  a  comparative  slight  thickness. 

In  San  Francisco  it  is  very  common  to  build  the  sidewalks  of 
cement,  with  steel  tension  bars  or  cables  imbedded  in  the  bottom,  so 
that  the  same  construction  answers  both  for  the  walk  and  for  cover- 
ing the  vault. 


,84  BUJLDTNG  CONSTRUCTION. 

If  brick  arches,  covered  with  sand  and  a  stone  or  brick  pavement 
are  used,  the  top  of  the  arch  should  be  coated  with  hot  asphalt. 

PAVEMENTS. 

93.  Although  these  do  not  come  under  the  heading  of  founda- 
tions they  are  more  nearly  .-elated  to  that  class  of  work  than  to  any 
other,  and  may  therefore  be  described  here. 

Pavements  may  be  made  either  of  thin  slabs  of  stone,  called  flag- 
ging, of  concrete,  finished  with  Portland  cement,  or  of  hard  bricks 
made  especially  for  the  purpose. 

When  large  slabs  of  stone  can  be  economically  obtained,  they  make, 
in  the  long  run,  the  most  economical  pavement,  and  one  that  is  about 
as  satisfactory  as  any. 

A  smoother  pavement  may  be  made  with  cement,  and  one  that  will 
be  practically  imperishable,  but  should  there  ever  be  occasion  tc  cut 
through  the  pavement,  or  to  change  the  grade,  the  cement  and  con- 
crete must  be  destroyed,  while  the  stone  flagging  can  be  taken  up  and 
relaid,  either*  in  the  same  place  or 
*jpi  •  T  |  used  somewhere  else.  A  stone  side- 

A::v-^^-'^^^^^^;;'-..>;-.:'J-.-'V:-y  wa^  can  a^so  ^e  repaired  easier  than 
'^^^^^^Pplrfi'e'nt.  either  of  the  others. 

F}  t  Stone  Pavements. — As  a  rule  only 

stones  that  split  with  comparatively 

smooth  and  parallel  surfaces  can  be  economically  used  for  pavements, 
for,  if  the  surface  of  the  stone  has  to  be  dressed,  it  will  generally  be 
more  economical  to  use  concrete  and  cement  or  hard  bricks. 

For  yards  and  areas,  flagging  from  2^  to  3  inches  thick  is  com- 
monly used,  the  edges  of  the  stones  being  trimmed  so  that  the  stones 
will  be  perfectly  rectangular,  and  the  joints  between  them  straight 
and  from  ^  to  f  inch  in  width. 

The  stones  should  be  laid  on  a  bed  of  sand  not  less  than  2  inches 
thick,  and  the  edges  should  be  bedded  in  cement,  as  shown  in  Fig. 
51,  the  cement  extending  some  3  or  4  inches  under  the  stone.  On 
•completion  the  joints  should  be  thoroughly  filled  with  i  to  i  cement 
-and  fine  sand,  and  struck  smooth  with  the  trowel. 

In  localities  where  the  soil  is  dry  and  not  affected  by  frost,  as  in 
Colorado,  New  Mexico,  etc.,  the  cement  is  generally  omitted  entirely 
the  stones  being  simply  bedded  in  sand  and  the  joints  filled  with  fine 
sand. 

This  answers  very  well  in  those  localities,  but  after  a  time  grass 
and  weeds  commence  to  spring  up  through  the  joints  in  yards  and 


PA  YEMEN TS.  85 

private  walks,  so  that  for  first-class  work  bedding  in  cement  should 
be  specified. 

Stone  sidewalks  are  generally  laid  on  a  bed  of  sand,  with  the  joints 
in  the  better  class  of  work  bedded  in  cement.  The  stones,  when  5 
feet  long,  should  be  at  least  3  inches  thick,  and  if  8  feet  long,  5  or  6 
inches  thick.  The  best  sidewalks  are  laid  in  one  course,  unless 
exceptionally  wide. 

In  localities  where  the  ground  is  affected  by  frost,  as  it  is  in  most 
of  the  Northern  States,  the  stones,  if  merely  laid  on  a  bed  of  sand, 
are  sure  to  become  displaced  and  out  of  level  within  one  or  two 
years.  To  prevent  this,  flagging  stones,  in  front  of  business  build- 
ings at  least,  should  have  a  solid  support  at  each  end. 


Fig.  52. 

Fig.  52  shows  the  manner  in  which  this  is  generally  provided,  and 
also  the  way  in  which  the  curb  and  gutter  is  supported.  The  curb- 
stone should  be  at  least  4  inches  thick,  and  on  business  streets  6 
inches. 

The  dwarf  wall  should  be  about  14  or  16  inches  thick  and  carried 
below  the  frost  line. 

If  the  sidewalk  is  laid  in  two  courses  a  slight  wall  of  brick  or  stone 
should  also  be  built  under  the  middle  of  the  walk  to  support  the  but- 
ting ends  of  the  stones. 

94.  Cement  Walks. — Cement  sidewalks  are  extensively  laid  in 
the  Western  States,  even  in  localities  where  excellent  flagging  stone 
is  abundant  and  cement  rather  dear. 

The  cement  walks  are  preferred  on  account  of  the  smooth  and  even 
surface  which  they  give.  When  properly  laid  they  are  also  very  dur- 
able. Cement  walks,  however,  should  only  be  laid  where  there  is  no 
danger  of  the  grade  being  altered,  and  after  the  ground  has  become 
thoroughly  settled  and  consolidated. 

The  durability  of  the  walk  depends  principally  upon  the  thickness 
of  the  concrete  and  the  quality  of  the  cement. 

Only  the  best  Portland  cement  should  be  used  for  the  finishing, 


86  BUILDING  CONSTRUCTION. 

although  natural  cements  are  sometimes  used  for  the  concrete.    Port- 
land cement  throughout,  however,  is  to  be  preferred. 

For  first-class  work  cement  walks  should  be  laid  as  follows: 
.The  ground  should  be  leveled  off  about  10  inches  below  the  fin- 
ished grade  of  the  walk  and  well  settled  by  tamping  or  rolling.  On 
top  of  this  a  foundation  5  inches  thick  should  be  laid  of  coarse 
gravel,  stone  chips,  sand  or  ashes,  well  tamped  or  rolled  with  a 
heavy  roller.  The  concrete  should  then  be  prepared  by  thoroughly 
mixing  i  part  of  cement  to  i  part  of  sand  and  3  of  gravel,  in  the  dry 
state,  then  adding  sufficient  water  from  a  sprinkler  to  make  a  dry 
mortar.  The  concrete  should  be  spread  in  a  layer  from  3  to  4  inches 
thick,  commencing  at  one  end,  and  should  be  thoroughly  tamped. 
Before  the  concrete  has  commenced  to  set  the  top  or  finishing  coat 
should  be  applied,  and  only  as  much  concrete  should  be  laid  at  a 
time  as  can  be  covered  that  day.  If  the  concrete  gets  dry  on  top  the 
finishing  coat  will  not  adhere  to  it.  The  top  coat  should  be  prepared 
by  mixing  i  part  of  high  grade  Portland  cement  with  i  part  of  fine 
sand,  or  i  part  clean,  sharp,  crushed  granite  (the  latter  is  the  best). 
The  materials  should  be  thoroughly  mixed  dry,  and  water  then  added 
to  give  the  consistency  of  plastic  mortar.  It  should  be  applied  with 
a  trowel  to  a  thickness  of  i  inch  and  carefully  smoothed  and  leveled 
on  top  between  straight-edges  laid  as  guides.  Used  in  the  above  pro- 
portion, one  barrel  of  Portland  cement  will  cover  about  40  square 
feet  of  concrete.  After  the  walk  is  finished  it  should  be  covered  with 
straw  to  prevent  it  drying  too  quickly. 

For  brick  paving  see  Section  381. 

SHORING,  NEEDLING  AND  UNDERPINNING. 

95.  The  direction  of  these  operations  when  required  is  generally 
left  to  the  contractor,  as  the  responsibility  for  the  successful  carry- 
ing out  of  the  work  devolves  upon  him. 

The  architect  will  be  wise,  however,  when  such  operations  are 
being  done  in  connection  with  work  let  from  his  office,  to  see 
that  proper  precautions  are  taken  for  safety,  and  that  all  beams  or 
posts  have  ample  strength  for  the  loads  they  have  to  support.  When 
heavy  or  difficult  work  has  to  be  done,  it  should,  if  possible,  be 
intrusted  to  some  careful  person  who  has  had  experience  in  that  class 
of  work,  as  it  is  almost  a  trade  by  itself. 

Shoring  is  supporting  the  walls  of  a  building  by  inclined  posts  or 
struts,  generally  from  the  outside,  while  its  foundations  are  being  car- 


SHORING  AND   UNDERPINNING.  87 

ried  down,  or  while  the  lower  portion  of  the  wall  is  being  removed 
and  girders  and  posts  substituted. 

The  usual  method  of  shoring  the  walls  of  buildings  not  exceeding 
three  stories  in  height,  especially  when  done  for  the  purpose  of  hold- 
ing up  the  walls  while  being  underpinned,  is  shown  in  Fig.  53. 

The  props  or  shores  are  inserted  in  sockets  cut  in  the  wall,  with 
their  lower  ends  resting  on  a  timber  crib  supported  on  the  ground. 
At  least  two  sets  of  shores  should  be  used,  one  to  support  the  wall  as 
low  down  as  possible  and  the  other  as  high  up  as  possible.  The  lat- 
ter shores  should  not  have  a  spread  at  the  bottom  of  more  than  one- 
third  of  their  height.  The  platform  should  be  made  large  enough  so 
as  not  to  bring  too  great  a  pressure  on  the  ground,  and  the  shores 
should  be  driven  into  place  by  oak  or  steel  wedges. 

The  shores  should  be  spaced  according  to  the  height  and  thick- 
ness of  the  wall,  and  all  piers  and  chimneys  should  be  shored.  Gen- 
erally a  spacing  of  6  feet  between  the  shores  will  answer. 

Only  a  part  of  the  foundation  should  be  removed  at  a  time,  and 
as  soon  as  three  sets  of  shores  are  in  place  the  wall  should  be  under- 
pinned, as  described  in  Section  97.  As  fast  as  the  wall  is  under- 
pinned the  first  set  of  shores  should  be  moved  along,  always  keeping 
two  sets  in  place,  and  working  under  or  with  one  set. 

Shoring  may  often  be  successfully  employed  for  holding  up  the 
corner  of  a  building  while  a  pier  or  column  is  being  changed,  and 
sometimes  when  the  lower  part  of  the  wall  is  to  be  removed  and  a 
girder  slipped  under  the  upper  portion.  In  the  latter  case,  however, 
needling  is  generally  more  successful  and  attended  with  less  risk. 

96.  Needling  is  supporting  a  wall,  already  built,  on  transverse 
beams  or  needles  placed  through  holes  cut  in  the  wall  and  supported 
at  each  end  either  by  posts,  jackscrews  or  grillage.  At  least  one  end 
of  the  horizontal  beam  should  be  supported  by  a  jackscrew. 

Wherever  a  long  stretch  of  wall  is  to  be  built  up  at  one  time,  and 
there  is  working  space  on  each  side  of  it,  needling  should  be 
employed. 

The  beams  must  be  spaced  near  enough  together  so  that  the  wall 
will  not  crack  between  them,  and  the  size  of  the  beams  carefully  pro- 
portioned to  the  weight  of  the  wall,  floors,  etc.  In  very  heavy  build- 
ings steel  beams  should  be  used  for  the  needles,  and  they  should  be 
spaced  not  more  than  2  feet  apart.  In  three  or  four-story  buildings 
the  needles  may  be  of  large  timber  and  spaced  from  4  to  6  feet  apart. 
Each  chimney  or  pier  should  have  one  or  more  needles  directly 
under  it. 


88  BUILDING  CONSTRUCTION. 

When  the  first  story  walls  or  supports  are  to  be  removed,  the  beams 
or  needles  are  usually  supported  on  long  timbers  having  a  screw 
under  the  lower  end  ;  or,  if  the  wall  is  very  high  or  thick,  a  grillage 
of  timber  is  built  up  and  the  jackscrews  are  placed  on  top  of  the 
grillage,  the  ends  of  the  needles  resting  on  a  short  beam  supported 
by  two  screws,  in  the  manner  shown  in  Fig.  54. 

When  it  is  desired  to  remove  the  first  story  wall  of  a  building  for 
the  purpose  of  substituting  posts  and  girders,  or  for  rebuilding  the 
wall,  holes  should  be  cut  in  the  wall  from  4  to  6  feet  apart,  accord- 
ing to  the  weight  to  be  supported  and  the  quality  of  the  brick  or  stone 
work,  and  at  such  a  height  that  when  the  needles  are  in  place  they 
will  come  a  few  inches  above  the  top  of  the  intended  girder.  Solid 
supports  should  then  be  provided  for  the  uprights,  the  needles  put 
through  the  wall,  and  posts,  having  screws  in  the  lower  ends,  set 
under  them,  the  base  of  the  screws  resting  on  the  solid  support  pre- 
viously provided.  If  the  needles  do  not  have  an  even  bearing  under 
the  wall,  iron  or  oak  wedges  should  be  driven  in  until  all  parts  of  the 
wall  bear  evenly  on  the  needles.  The  jacks  should  then  be  screwed 
up  until  the  wall  is  entirely  supported  by  the  needles,  care  being 
taken,  however,  not  to  raise  the  wall  after  the  weight  is  oh  the  needles. 

The  wall  below  may  then  be  removed,  the  girder  and  posts  put  in 
place,  and  the  space  between  the  girder  and  the  bottom  of  the  wall 
built  up  with  brickwork,  the  last  course  of  brick  or  stone  being 
made  to  fit  tightly  under  the  old  work.  The  needles  may  then  be 
withdrawn  and  the  holes  filled  up. 

97.  Underpinning  is  carrying  down  the  foundations  of  an  exist- 
ing building,  or,  in  other  words,  putting  a  new  foundation  under  the 
old  ones. 

New  footings  may  generally  be  put  under  a  one  or  two-story  build- 
ing resting  on  firm  soil  without  shoring  or  supporting  the  walls  above, 
the  common  practice  being  to  excavate  a  space  only  2  to  4  feet  long 
under  the  wall  at  a  time,  sliding  in  the  new  footing  and  wedging  up 
with  stone,  slate,  or  steel  wedges. 

Where  the  underpinning  is  to  be  3  feet  high  or  more,  or  where  the 
building  is  several  stories  in  height,  the  walls  should  be  braced  or 
supported  by  shores  or  needles. 

The  usual  method  of  underpinning  the  walls  of  buildings  where  a 
cellar  is  to  be  excavated  on  the  adjoining  lot  is  shown  in  Fig.  53. 

Pits  should  first  be  dug  to  the  depth  of  the  new  footing,  and  a  tim- 
ber platform  built  as  shown  ;  the  shores  should  then  be  put  in  place 
and  wedged  up  with  oak  wedges. 


SHORING  AND   UNDERPINNING. 


89 


Steel  Wedges. 


ELEVATION  ' 

Fig.  S3- 

Sections  about  3  feet  wide  between  the  shores  should  then  be  exca- 
vated under  the  wall,  new  footing  stones  laid,  and  the  space  between 
the  new  and  old  footings  filled  with  brick  or  stone  work.  Where  the 
height  between  the  new  and  old  footings  does  not  exceed  5  feet, 
granite  posts,  if  available,  offer  special  advantages  for  underpinning. 


9° 


B  UILDING  CONS TR  UCTION. 


They  should  be  from  12  to  18  inches  wide  on  the  face  and  of  a  thick- 
ness equal  to  that  of  the  wall;  they  should  be  cut  so  as  just  to  fit 
between  the  new  and  old  work,  and  with  top  and  bottom  surfaces 
dressed  square  ;  they  should  be  set  in  a  full  bed  of  Portland  cement 
mortar,  and  the  top  joint  also  filled  with  mortar  and  brought  to  a 
bearing  with  steel  wedges. 

If  granite  posts  are  not  available  good  flat  stone  or  hard  brick  laid 
in  cement  mortar  may  be  used  instead,  wedging  up  under  the  old 
wall  with  pieces  of  slate  driven  into  the  upper  bed  of  cement,  or  with 
steel  wedges.  Under  heavy  walls  the  latter  only  should  be  used.  If 
the  bottom  of  the  old  footings  is  of  soft  brickwork,  pieces  of  hard  flag- 


Jack-screw 


New  Foot  ing 


ging,  with  a  full  bed  of  cement  mortar,  may  be  placed  under  them, 
and  the  wedges  driven  under  the  flagging  so  as  to  bring  the  latter 
"  hard  up  "  under  the  old  work.  The  portions  of  wall  between  these 
sections  should  then  be  underpinned  in  the  same  way  and  the  shores 
moved  along. 

Where  granite  posts  are  used  they  may  be  placed  3  feet  apart  and 
the  space  between  built  up  with  flat  rubble  or  hard  brick,  wedged  up 
under  the  old  wall  with  slate. 

If  the  soil  under  the  old  building  is  sufficiently  firm,  so  that  it  will 
not  cave  or  "run  away,"  and  there  is  working  space  beneath  the 
lower  floor,  the  ground  may  be  leveled  off,  a  platform  of  plank  and 
timbers  placed  on  top  of  it,  and  needles  used  for  supporting  the  wall 


SHORING  AND  UNDERPINNING.  91 

as  shown  in  Fig.  54.  Where  needles  are  used  all  of  the  underpin- 
ning under  the  portion  of  wall  supported  may  be  put  in  at  the  same 
time. 

The  underpinning  should  be  done  as  quickly  as  possible  after  the 
shores  or  needles  are  in  place/  so  as  not  to  require  their  support  for  a 
longer  time  than  necessary.  The  needles  or  shores  should,  however, 
not  be  removed  until  the  cement  has  had  time  to  set. 

98.  Chicago  Practice. 

In  building  the  modern  tall  office  building  in  Chicago  the  foundations  generally 
have  to  go  below  those  of  the  adjacent  buildings,  and,  the  ground  being  compress- 
ible, new  party  wall  foundations  are  almost  invariably  required.  The  consequence 
is  that  the  old  walls  have  to  be  supported  while  the  new  foundation  is  being  put 
under  them.  This  is  usually  done  by  means  of  steel  needles  placed  from  12  to  24 


l^r/oor 


Id'brick  urall 
Ist  Floor 


"Jack  Jcrewj. 

Columns  similar  to  the* 
to  be  provided  when  netc 
building  is  puC  up  on  tfiij 
jicie  of  party  wall. 


Fig.  55- 


inches  apart,  their  ends  resting  on  long  beams  placed  parallel  with  the  wall  and 
supported  by  jackscrews.  Very  often  an  entire  wall  is  supported  in  this  way,  sev- 
eral hundred  jackscrews  being  required  for  the  purpose. 

In  erecting  buildings  of  skeleton  construction  it  is  often  impracticable  to  remove 
the  old  wall,  and  the  new  building  is  supported  by  iron  columns  placed  against  the 
wall  and  resting  on  a  new  foundation  put  in  under  the  old  one.  In  building  the 
New  York  Life  Building  in  Chicago  such  was  the  case,  and  the  adjacent  wall  was 
held  up  by  jackscrews,  as  shown  in  Fig.  55,  which  were  inserted  to  keep  the  wall 
in  place  during  the  settlement  of  the  new  work.  As  the  new  foundations  settled 
the  jacks  were  screwed  up,  so  as  to  keep  the  old  wall  in  its  original  position.  In 
this  case  the  jacks  were  left  in  place. 

99.  Bracing. — Where  buildings  have  been  built  with  a  party 
wall,  and  one  of  the  buildings  is  torn  down,  leaving  the  adjacent 


92 


BUILDING  CONSTRUCTION. 


walls  unsupported,  they  should  be  protected  from  falling  by  spreading 
braces  or  inclined  shores,  according  to  special  conditions. 

Where  there  is  a  building  on  the  other  side  of  the  vacant  lot,  and 
within  40  or  50  feet,  the  walls  of  both  buildings  may  be  best  sup- 
ported by  spreading  braces,  after  the  manner  shown  in  Fig.  56. 

If  the  distance  between  the  buildings  does  not  exceed  25  feet,  the 
braces  may  be  arranged  as  shown  at  A  or  B.     If  more  than  25  feet, 
the  braces  must  be  trussed  in  a  manner  similar  to  that  shown  at  C. 
[Iron   or  steel   rods  are   preferable  for  the  vertical  ties,  as  they 

can  be  screwed  up,  and 
any   sagging  caused   by 
shrinkage   in    the   joints 
3  K      "HI  0       fl  It-^T      iiT-H  E       overcome.] 

If  the  buildings  are 
very  high  every  other 
story  should  be  braced. 
The  ends  of  the  braces 
or  trusses  must  be  sup- 
ported vertically,  so  that 
they  will  not  slip  down.  Where  there  are  offsets  in  the  wall  these 
may  serve  for  a  vertical  support ;  if  there  are  no  offsets,  then  the 
braces  should  be  supported  by  vertical  posts,  starting  from  the  foun- 
dation, or  sockets  might  be  cut  in  the  wall  and  corbels  let  in  and 
bolted  through  from  the  inside. 

A  truss  should  be  placed  opposite  the  fronts,  and  should  be  propor- 
tioned so  as  to  resist  the  thrust  from  any  arches  there  may  be  in  the 
front.  The  braces  should  be  about  8x8  or  10x10  inches  in  size, 
with  6x12  uprights  against  the  wall,  the  ends  of  the  braces  being 
mortised  into  the  uprights. 

If  there  is  no  wall  opposite  the  building  to  be  braced,  then  inclined 
braces  must  be  used,  arranged  in  a  similar  manner  to  the  shores 
shown  in  Fig.  53,  only  with  a  greater  inclination.  The  ends  of  the 
braces  should  be  brought  to  a  bearing  by  oak  wedges. 


Fig.  56. 


CHAPTER  IV. 
LIMES,  CEMENTS  AND  MORTARS. 


There  is  hardly  any  material  used  by  the  architect  or  builder  upon 
which  so  much  depends  as  upon  mortar  in  its  different  forms,  and  it 
is  important  that  the  architect  should  be  sufficiently  familiar  with  the 
different  kinds  of  limes  and  cements  to  know  their  properties  and  in 
what  kind  of  work  each  should  be  used.  He  should  also  be  able  to 
judge  of  the  quality  of  the  materials  with  sufficient  accuracy  to  pre- 
vent any  that  is  actually  worthless  from  being  used,  and  should  have 
some  knowledge  of  mortar  mixing. 

IOO.  Lime. — Common  lime,  sometimes  called  quicklime  or  caus- 
tic lime,  is  produced  by  the  calcination  (or  heating  to  redness)  of 
limestones  of  varying  composition.  This  is  done  by  burning  the  stone 
in  a  kiln  with  an  oviod  vertical  section  and  circular  horizontal  sec- 
tion. The  broken  stone  and  fuel  (generally  coal)  are  put  in  in  layers, 
the  fire  lighted  at  the  bottom,  and  as  the  lime  drops  to  the  bottom 
new  layers  of  stone  and  coal  are  put  in  at  the  top,  so  that  the  kila 
may  be  kept  burning  for  weeks  at  a  time.  The  limestones  from 
which  limes  and  cements  are  produced  differ  greatly  in  their  compo- 
sition, ranging  from  pure  carbonate  of  lime,  such  as  white  chalk  or 
marble,  to  stones  containing  10  per  cent,  or  more  of  impurities,  such 
as  silica,  alumina  (clay),  magnesia,  oxide  of  manganese  and  traces  of 
the  alkalies.  The  quality  of  the  lime  will  consequently  depend  much 
upon  the  percentage  of  impurities  contained  in  the  stone  from  which 
it  is  made.  Lime  is  manufactured  in  nearly  every  State  in  the 
Union,  each  locality  generally  producing  its  own  supply. 

There  is  considerable  difference,  however,  in  the  limes  of  different 
localities,  and  before  using  a  new  lime  the  architect  should  make 
careful  inquiries  regarding  its  quality,  and  if  it  has  not  been  much 
used  it  would  be  better  to  procure  a  lime  of  known  quality,  at  least 
for  plastering  purposes  ;  for  common  mortar  it  is  not  necessary  to  be 
so  particular. 

In  most  parts  of  New  England  lime  is  sold  by  the  barrel,  but  in 
many  parts  of  the  country  it  is  sold  in  bulk,  either  by  the  bushel  or 
by  weight. 


94 


BUILDING  CONSTRUCTION, 


101.  Characteristics  of  Good    Lime.— Good   lime   should 
possess  the  following  characteristics:    i.  Freedom  from  cinders  and 
clinkers,  with  not  more  than  10  per  cent,  of  other  impurities.     2.   It 
should  be  in  hard  lumps,  with  but  little  dust.     3.   It  should  slake 
readily  in  water,  forming  a  very  fine,  smooth  paste,  without  any  resi- 
due.    4.  It  should  dissolve  in  soft  water. 

There  are  some  limes  which  leave  a  residue  consisting  of  small 
stones  and  silica  and  alumina  in  the  mortar  box,  after  the  lime  is 
drained  off.  Such  limes  may  answer  for  making  mortar  for  building 
purposes,  but  should  not  be  used  for  plastering  if-  a  better  quality  of 
lime  can  be  procured. 

102.  Slaking  and  Making  into  Mortar. — The  first  step  in 
the  manufacture  of  lime  mortar  consists  in  the  slaking  of  the  lime. 
This  is  generally  done  by  putting  the  lime  in  a  water-tight  box  and 
adding  water  either  through  a  hose  or  by  pails,  the  amount  of  water 
depending  upon  the  quality  of  the  lime.     Lime  such  as  is  sold  in  New 
England  requires  a  volume  of  water  equal  to  two  and  one-half  to 
three  times  the  volume  of  the  lime.     The  water  is  rapidly  absorbed 
by  the  lime,  causing  a  great  elevation  of  temperature,  the  evolution  of 
hot  and  slightly  caustic  vapor,  and  the  bursting  of  the  lime  into  pieces, 
and  finally  the  lime  is  reduced  to  a  powder,  the  volume  of  which  is 
from  two  and  a  half  to  three  and  a  half  times  the  volume  of  the  orig- 
inal lime.     In  this  condition  the  lime  is  said  to  be  slaked  and  is  ready 
for  making  into  mortar.     The  Thomaston  and  Rockland  (Maine) 
lime,  as  also  most  other  limes  sold  in  New  England,  slake  without 
leaving  a  residue,  and  the  mortar  is  made  by  mixing  clean,  sharp 
sand  with  the  slaked  lime  in  the  proportion  of  i  part  of  lime  to  about 
5  of  sand  by  volume.     Practically  the  proportion  of  sand  is  seldom, 
if  ever,  measured,  but  the  sand  is  added  till  the  person  mixing  the 
mortar  thinks  it  is  of  the  proper  proportion.     For  brickwork  over  a 
certain  proportion  of  sand  cannot  well  be  added,  for  if  there  is  too 
much  sand  in  the  mortar  it  will  stick  to  the  trowel  and  will  not  work 
easily.     With  stonework  the  temptation  is  always  to  add  too  much 
sand,  as  sand  is  generally  cheaper  than  lime.     The  architect  or  super- 
intendent should  take  pains  to  make  himself  familiar  with  the  appear- 
ance of  good  mortar,  so  that  he  can  readily  tell  at  a  glance  if  it  has 
too  much  sand.     Mortar  that  contains  a  large  proportion  of  lime  is 
said  to  be  rich;  if  it  has  a  large  proportion  of  sand  and  works  hard  it 
is  said  to  be  stiff,  and  to  make  it  work  more  readily  it  is  tempered  by 
the  addition  of  water.     Tempered  mortar  looks  much  richer  than 
stiff  mortar,  though  it  may  not  be  so.     If  the  mortar  slides  readily 


LIMES,  CEMENTS  AND  MORTARS.  95 

from  the  trowel  it  is  of  good  quality,  but  if  the  mortar  sticks  to  the 
trowel  there  is  too  much  sand  in  proportion  to  the  lime.  The  color 
of  the  mortar  depends  much  upon  the  kind  and  color  of  the  sand 
used. 

Many,  of  the  limes  used  in  the  Western  States  when  slaked  leave  a 
residue  of  stones,  lumps  and  gravel,  so  that  instead  of  mixing  the 
mortar  in  the  same  box  in  which  the  lime  is  slaked,  a  larger  propor- 
tion of  water  is  added,  and  the  slaked  lime  and  water  (about  as  thick 
as 'cream)  is  run  off  through  a  fine  sieve  into  another  box,  in  which 
the  mortar  is  mixed.  Such  lime  does  not  make  as  good  mortar  as 
that  which  leaves  no  impurities,  but  it  does  very  well  for  use  in  brick 
and  stone  work. 

The  general  custom  in  making  lime  mortar  is  to  mix  the  sand  with 
the  lime  as  soon  as  the  latter  is  slaked  and  letting  it  stand  until 
required  for  use.  Much  stronger  and  better  mortar  would  be 
obtained,  however,  if  the  sand  were  not  mixed  with  the  slaked  lime 
until  the  mortar  was  needed. 

103.  Sand. — The  sand  used  in  making  mortar  should  be  angular 
in  form,  of  various  sizes,  and  absolutely  free  from  all  dust,  loam, 
clay  or  earthy  matter,  and  also  from  large  'stones.     It  is  generally 
necessary  to  pass  the  sand  through  a  screen  to  insure  the  proper 
degree  of  fineness.     For  rough  stonework  a  combination  of  coarse 
and  fine  sand  makes  the  strongest  mortar.     For  pressed  brickwork  it 
is  necessary  to  use  very  fine  sand.     The  architect  or  superintendent 
should  carefully  inspect  the  sand  furnished  for  the  mortar,  and  if  he 
has  any  doubts  of  its  cleanliness,  a  handful  put  in  a  tumbler  will  at 
once  settle  the  question,  as  the  dirt  will  separate  and  rise  to  the  top. 
Another  simple  method  of  testing  sand  is  to  squeeze  some  of  the 
moist  sand  in  the  hand,  and,  if  upon  opening  the  hand  the  sand  is 
found  to  retain  its  shape,  it  must  contain  loam  or  clay,  but  if  it  falls 
down  loosely  it  may  be  considered  as  clean.     Sand  containing  loam 
or  clay  should  be  at  once  rejected  and  ordered  from  the  premises. 
As  a  rule,  it  is  better  that  the  sand  should  be  too  coarse  rather  than 
too  fine,  as  the  coarse  sand  takes  more  lime  and  makes  the  strongest 
mortar.     Some  unscrupulous  masons  may  attempt  to  use  fine  sandy 
loam  in  their  mortar,  as  it  takes  the  place  of  lime  in  making  the  mor- 
tar work  easily  ;  but,  of  course,  it  correspondingly  weakens  the  mor- 
tar, and  its  use  should  never  be  permitted. 

104.  White  and  Colored  Mortars. — White  and  colored  mor- 
tars to  be  used  in  laying  face  brick  should  be  made  from  lime  putty 
and  finely  screened  sand.     After  the  slaked  lime  has  stood  for  several 


96  BUILDING  CONSTRUCTION. 

days  the  water  evaporates  and  the  lime  thickens  into  a  heavy  paste, 
much  like  putty,  and  from  which  it  takes  its  name  of  lime  putty.  By 
the  time  the  putty  is  formed  the  lime  is  sure  to  be  well  slaked  and  will 
not  then  swell  or-"  pop."  Colored  mortar  is  made  by  the  addition  of 
mineral  colors  to  the  white  mortars.  Colored  mortar  should  never  be 
made  with  freshly  slaked  lime,  but  only  with  lime  putty  at  least  three 
days  old.  For  Mortar  Colors  see  Section  148. 

Common  lime  when  slaked  and  evaporated  to  a  paste  may  be  kept 
for  an  indefinite  time  in  that  condition  without  deterioration,  if  pro- 
tected from  contact  with  the  air  so  that  it  will  not  dry  up.  It  is  cus- 
tomary to  keep  the  lime  paste  in  casks  or  in  the  boxes  in  which  it  was 
slaked,  covered  over  with  sand,  to  be  subsequently  mixed  with  it  in 
making  the  mortar.  Clear  lime  putty  may  be  kept  for  a  long  time  in 
casks,  for  use  in  making  colored  mortar,  only  a  little  mortar  being 
made  up  at  a  time. 

105.  Setting. — Lime  paste  or  mortar  does  not  set  like  cement, 
but  gradually  absorbs  carbonic  acid  from  the  air  and  becomes  in  time 
very  hard  ;  the  process,  however,  requires  from  six  months  to  several 
years,  according  to  the  thickness  of  the  mortar  and  its  exposure  to 
the  atmosphere.     If  permitted  to  dry  too  quickly  it  never  attains  its 
proper  strength.     If  frozen,  the  process  of  setting  is  delayed  and  the 
mortar  is  much  injured  thereby.     Alternate  freezing  and  thawing 
will  entirely  destroy  the  strength  of  the  mortar.     Lime  mortar  will  not 
harden  under  water,   nor  in  continuously  damp  places,  nor  when 
excluded  from  contact  with  the  air. 

106.  Preserving. — Fresh  burned  lime  will  readily  absorb  mois- 
ture  from  a  damp   atmosphere,  and  will   in   time   become  slaked 
thereby  losing  all  of  its  valuable  qualities  for  making  mortar.     It 
is  therefore  important  that  great  care  should  be   taken   to   secure 
freshly  burned  lime  and  to  protect  it  from  dampness  until  it  can  be 
used.     If  the  lime  is  purchased  in  casks  it  should  be  kept  in  a  dry 
shed  or  protected  by  canvas,  and  if  it  is  bought  in  bulk  it  should  be 
kept  in  a  water-tight  box  built  for  the  purpose. 

On  no  account  should  the  superintendent  permit  of  the  use  of  air- 
slaked  lime,  as  it  is  impossible  to  make  good  mortar  of  it. 

107.  Durability  of  Lime  Mortar.— Good  lime  mortar,  when 
protected   from    moisture,  has  sufficient    strength  for  all   ordinary 
brickwork,  except  when  heavily  loaded,  as  in  piers,  and  continues  to 
grow  harder  and  stronger  every  year.     The  writer  has  often  seen 
instances  in  old  walls  where  the  lime  mortar  was  as  strong  as  the 


LIMES,  CEMENTS  AND  MORTARS.  97 

bricks,  and  where  the  adhesion  of  the  mortar  to  the  bricks  was  greater 
than  the  cohesion  of  the  particles  of  the  bricks. 

A  specimen  of  mortar,  supposed  to  be  the  most  ancient  in  exist- 
ence, obtained  from  a  buried  temple  on  the  island  of  Cyprus,  was 
found  to  be  hard  and  firm,  and  upon  analysis  appeared  to  be  made 
of  a  mixture  of  burnt  lime,  sharp  sand  and  gravel,  some  of  the  frag- 
ments being  about  £  inch  in  diameter.  The  lime  was  almost  com- 
pletely carbonized.* 

Lime  mortar,  however,  attains  its  strength  slowly,  and  where  high 
buildings  are  built  rapidly  the  mortar  in  the  lower  story  does  not 
have  time  to  get  sufficiently  hard  to  sustain  the  weight  of  the  upper 
stories,  and  for  such  work  natural  cement  should  be  added  to  the 
lime  mortar. 

HYDRAULIC  LIME. 

I08.  Hydraulic  limes  are  those  containing,  after  burning,  enough 
lime  to  develop,  more  or  less,  the  slaking  action,  together  with  suffi- 
cient of  such  foreign  constituents  as  combine  chemically  with  lime 
and  water,  to  confer  an  appreciable  power  of  setting  under  water,  and 
without  access  of  air. 

The  process  of  setting  is  entirely  different  from  that  of  drying, 
which  is  produced  simply  by  the  evaporation  of  the  water.  Setting 
is  a  chemical  action  which  takes  place  between  the  water,  lime  and 
other  constituents,  causing  the  paste  to  harden  even  when  under 
water. 

Hydraulic  lime  or  cement  should  not  be  used  after  it  has  com- 
menced to  set,  as  the  setting  will  not  take  place  a  second  time  and 
the  strength  of  the  mortar  will  be  lost. 

In  the  great  majority  of  natural  hydraulic  limes  commonly  used 
for  making  mortar,  the  constituent  which  confers  hydraulicity  is  clay, 
although  silica  also  has  the  same  effect. 

Hydraulic  limes  containing  clay  may  be  arranged  in  three  classes, 
according  to  their  amount  of  hydraulic  energy  : 

1.  "Feebly  hydraulic — containing  10  to  20  per  cent,  of  impurities. 
This  slakes  in  a  few  minutes,  with  crackling,  heat  and  emission  of 
vapor.     If  made  into  a  paste  and  immersed  in  water  in  small  cakes, 
it  will  harden  so  as  to  resist  crushing  between  the  thumb  and  finger 
in  from  twelve  to  fifteen  days. 

2.  "  Ordinary  hydraulic — containing  17  to  24  per  cent,  of  impuri- 
ties.    Slakes  after  an  hour  or  two,  with  slight  heat  and  fumes,  with- 
out crackling.     Sets  under  water  in  six  or  eight  days. 

*  William  Wallace,  Ph.D.,  F.  R.  S    E.,  in  London  Chemical  News,  No.  281. 


98  BUILDING  CONSTRUCTION. 

3.  "  Eminently  hydraulic — containing  at  least  20  per  cent  of  inipur 
ities.  Slakes  very  slowly  and  with  great  difficulty,  with  slight  heat. 
Sets  under  water  in  twelve  to  twenty  hours  and  becomes  hard  in  two 
to  four  days."  * 

Artificial  hydraulic  lime  can  be  manufactured  by  mixing  together, 
in  proper  proportions,  thoroughly  slaked  common  lime  and  unburnt 
clay,  then  burning  and  grinding  in  much  the  same  manner  as  in  the 
manufacture  of  Portland  cement;  but  as  the  process  of  manufacture  is 
nearly  as  expensive  as  for  making  Portland  cement,  it  is  more  profit- 
able to  make  cement,  on  account  of  its  superior  hydraulic  energy. 

No  hydraulic  lime  is  manufactured,  artificially,  in  the  United 
States,  and  but  very  few  hydraulic  limes  are  in  use. 

A  gray  lime  is  obtained  at  Morrison  and  a  few  other  locations  in  Colorado 
which  hardens -under  water  and  makes  very  strong  mortar.  It  is  also  sometimes 
used  for  making  concrete. 

A  very  simple  experiment  will  determine  if  a  lime  is  hydraulic  or 
not :  Make  a  small  cake  of  the  lime  paste,  and  after  it  has  com- 
menced to  stiffen  in  the  air,  place  it  in  a  dish  of  water  so  that  it  will 
be  entirely  immersed.  If  it  possesses  hydraulic  properties  it  will 
gradually  harden,  but  if  it  is  not  hydraulic  it  will  soften  and  dissolve. 

Hydraulic  lime  mortar  is  made  in  the  same  way  as  common  lime 
mortar,  care  being  taken  to  use  sufficient  paste  to  coat  all  grains  of 
sand  and  to  fill  up  the  voids  between  them. 

109.  Pozzuolanas  is  a  name  given  to  certain  clayey  earths  con- 
taining 80  to  90  per  cent,  of  clay,  with  a  little  lime  and  small  quanti- 
ties of  magnesia,  potash,  soda,  oxide  of  iron,  or  manganese. 

When  finely  powdered  in  their  raw  state  and  added  to  lime  mortar 
they  confer  hydraulic  properties  to  a  considerable  degree. 

Natural  Pozzuolana  is  a  naturally-burnt  earth  of  volcanic  origin 
found  at  Pozzuoli,  near  Vesuvius,  and  in  the  caverns  of  St.  Paul, 
near  Rome.  It  is  found  in  the  form  of  powder,  and  when  sifted  is 
used  all  along  the  Mediterranean  coast  for  making  hydraulic  mortars. 

Beton  (similar  to  concrete)  as  prepared  in  that  region  is  generally 
made  of  Pozzuolana,  lime  and  aggregates  in  the  following  proportions: 

Pozzuolana I2  parts. 

Sand 6       .. 

Good  quicklime o       «« 


Small  stones., 


13 

Ground  slag 3 

'  Ira  O.  Baker  in  "  Masonry  Construction." 


LIMES,  CEMENTS  AND  MORTARS.  99 

Pozzuolana  is  not  used  in  this  country,  but  as  the  name  is  fre- 
quently found  in  books  on  masonry  construction,  it  is  well  for  the 
young  architect  to  know  what  it  is. 

Brick  dust,  mixed  with  common  lime,  produces  a  feebly  hydraulic 
mortar,  and  adds  materially  to  its  strength. 

HYDRAULIC  CEMENTS. 

Hydraulic  cements  are  made  by  calcining  limestones  containing 
from  30  to  60  per  cent,  of  clay. 

They  do  not  slake  or  break  up  like  lime,  and  their  paste  sets  very 
quickly,  either  in  air  or  water. 

They  may  be  divided  into  two  classes: 

1.  Natural  cements. 

2.  Artificial  cements. 

110.  Natural  Cements  are  made  from  a  natural  rock,  of  which 
the  principal  ingredients  are  carbonate  of  lime,  carbonate  of  mag- 
nesia and  clay.  The  stone,  after  being  quarried,  is  broken  into 
pieces  of  a  suitable  size  and  mixed  with  anthracite  coal  and  burned 
in  kilns  specially  constructed  for  the  purpose.  Great  care  is  required 
in  selecting  and  preparing  the  stone  for  the  kiln  and  in  burning  it  to 
a  consistent  degree  of  calcination. 

After  calcining  the  material  is  drawn  out  of  the  kilns  and  care- 
fully inspected.  That  which  is  properly  burned  is  sent  to  the  mill  to 
be  finely  ground  between  ordinary  millstones,  and  the  underburned 
or  over-calcined  thrown  away. 

Natural  cements  weigh  about  two-thirds  as  much  as  Portland 
cement,  are  very  quick  setting  and  have  less  ultimate  strength. 
They  attain  their  full  strength,  however,  sooner  than  the  Portland 
cements,  and  are  sufficiently  strong  for  all  ordinary  building  opera- 
tions. 

They  have  been  used  in  many  of  the  largest  building  and  engi- 
neering wrorks  in  this  country  with  perfectly  satisfactory  results,  and 
their  use  is  extending  every  year. 

They  are  sold  at  a  less  price  than  Portland  cements,  and  in  locali- 
ties where  the  cost  of  transportation  is  not  excessive  are  almost  exclu- 
sively used  for  cement  mortar. 

in.  Distribution  of  Natural  Cements. — "In  no  other  coun- 
try in  the  world  is  there  to  be  found  cement  rock  formations  which 
are  at  all  to  be  compared  with  those  so  well  distributed  throughout 
the  United  States.  .  .  .  Here  we  have  immense  beds  of  cement 
rock  absolutely  free  from  any  extraneous  substances,  perfectly  pure 


I0o  BUILDING  CONSTRUCTION. 

and  clean,  with  layer  upon  layer,  extending  for  thousands  of  feet 
without  appreciable  variation  in  the  proportion  of  the  ingredients."* 

Natural  cements- are  manufactured  in  very  many  localities  through- 
out this  country,  the  cement  being  commonly  known  by  the  name  of 
the  place  from  which  the  stone  is  obtained,  although,  as  there  are 
often  several  manufactories  in  the  same  locality,  there  may  be  several 
brands  of  cement  made  from  the  same  rock.  The  difference  in  the 
quality  of  such  brands  is  generally  due  to  the  care  exercised  in 
their  manufacture. 

The  localities  in  which  natural  cements  are  made  on  an  extensive 
scale  are  as  follows: 

Rosendale,  N.  Y. — Natural  cement  was  first  made  in  this  country  in  the  town 
of  Rosendale,  Ulster  County,  N.  Y.,  during  the  year  1823,  for  use  in  building  the 
Delaware  and  Hudson  Canal.  Since  then  inexhaustible  deposits  have  been  found 
of  the  fine-grained  natural  stone  out  of  which  Rosendale  cement  is  made,  and 
there  are  several  companies  which  manufacture  cement  from  this  rock,  each  hav- 
ing a  special  brand  for  their  product.  Owing  to  the  length  of  time  for  which 
they  have  been  used,  and  the  special  advantages  enjoyed  for  transportation  and 
nearness  to  the  great  building  centres  of  the  country,  Rosendale  cement  is  more 
widely  known  than  any  other  of  the  natural  cements.  It  is  generally  of  a  very 
good  quality  and  well  suited  for  building  operations. 

Very  good  natural  rock  cements  are  also  made  at  Buffalo,  Akron  and  Howe's 
Cave,  N.  Y. 

Louisville,  Ky. — Louisville  cement,  made  from  natural  rock  quarried  at  this 
place,  is  probably  the  leading  natural  cement  beyond  the  Alleghenies,  the  product 
being  exceeded  only  by  the  production  from  the  Rosendale  district.  There  are 
several  brands  of  this  cement  in  the  market,  and  they  find  their  way  as  far  west  as 
the  Rocky  Mountains. 

At  Utica,  III.,  a  natural  cement  has  been  manufactured  since,  1838.  This  cement 
has  always  stood  well  in  public  favor,  and  is  largely  used  throughout  the  West. 

At  La  Salle,  III.,  a  natural  cement  is  manufactured  from  the  same  rock  forma- 
tion as  that  running  through  Utica,  111. 

The  Afihuaukee  Cement  Co.  manufactures  a  natural  cement  from  rock  obtained 
near  Milwaukee,  Wis.,  which  is  extensively  used. 

Mankato,  Minn. — A  cement  rock  of  the  very  best  quality  exists  at  this  place, 
and  the  manufactured  product  has  obtained  a  strong  foothold  in  the  markets  of  the 
Northwest. 

Cement,  Ga. — The  cement  manufactured  from  stone  quarried  at  this  place 
"probibly  has  no  superior  in  this  country.  Used  as  an  exterior  plaster  on  a 
house  in  Charleston  in  1852,  the  stucco  still  remains  unimpaired,  while  the  sand- 
stone lintels  over  the  windows  have  long  since  been  worn  away." 

Fort  Scott,  A'an.—A.  natural  cement  has  been  manufactured  at  this  place  since 
1867.  The  product  resembles  that  of  Cement,  Ga. 

*  Uriah  Cummings  in  the  Brickbuildtr. 


L7MES,  CEMENTS  AND  MORTARS. 


101 


Natural  cements  are  also  manufactured  at  Siegfried's  Bridge.  Lehigh  Valley, 
Pa.;  Balcony  Falls.  Va.,  and  Cumberland,  Md.,  and  to  a  limited  extent  at  several 
localities  in  the  West. 

[An  extended  description  of  the  natural  cements  manufactured  in 
this  country  is  given  in  a  series  of  articles  by  Uriah  Cummings  in 
the  Brickbuilder  for  1895.] 

112.  Analysis  of  Natural  Cements. — The  following  table, 
giving  the  chemical  constituents  of  the  leading  natural  cements,  wilL 
be  found  useful  in  comparing  the  products  from  different  localities: 

TABLE  VII.— TABLE  OF  ANALYSIS— NATURAL  ROCK  CEMENTS. 


NUMBER. 

SILICA. 

ALUMINA. 

IRON  OXIDE. 

LIME. 

MAGNESIA. 

POTASH 
AND  SODA. 

CARBONIC 
ACID,  WATER. 

I 

24  IO 

2  6l 

6  20 

6  16 

5  V) 

IS  21 

2 

14  66 

5  IO 

I  OO 

18  oo 

6  16 

4  84 

3 

23  16 

6  11 

i  71 

36  O8 

20  38 

">  27 

7  °7 

4  • 

26  40 

6  28 

I  OO 

4  24 

7  86 

5  • 

25  28 

7  85 

I  41 

4  25 

7  04 

6  .   . 

10  84 

7  75 

211 

Ij  77 

7  

27  IO 

7  14 

I  8O 

<JC   q8 

18  oo 

6  80 

2  98 

8  

28  18 

II  71 

2  2Q 

2  21 

Q  OO 

2  44 

9  

27  6q 

8  64 

2  OO 

42  12 

14  "?S 

3  oo 

IO  

8  56 

2  08 

61  62 

o  40 

2  OO 

o  80 

II  

21  12 

i  Q7 

7  76 

2  OO 

12  

27  60 

10  60 

o  80 

7  26 

7  42 

2  (X) 

13  

11  42 

10  04 

6  oo 

12  7Q 

o  50 

7  66 

14  

22  58 

7  23 

•I  -1C 

48  18 

je  OO 

3  66 

15  

26  61 

10  64 

1  SO 

42  12 

11  12 

2  OO 

2  OI 

16 

o  08 

REFERENCE; 

1.  Buffalo  Hydraulic  Cement,  Buffalo,  N.  Y. 

2.  Utica  Hydraulic  Cement,  Utica,  111. 

3.  Milwaukee  Hydraulic  Cement,  Milwaukee,  Wis. 

4.  Louisville  Hydraulic  Cement,  "Fern  Leaf."  Louisville,  Ky. 

5.  Louisville  Hydraulic  Cement,  "  Hulme,"  Louisville,  Ky. 

6.  Rosendale  Hydraulic  Cement,  "  N.  Y.  &  R.,"  Rosendale,  N.  Y. 

7.  Rosendale  Hydraulic  Cement,  "Hoffman,"  Rosendale,  N.  Y. 

8.  Cumberland  Hydraulic  Cement,  Cumberland,  Md. 

9.  Akron  Hydraulic  Cement,  "Cummings,"  Akron,  N.  Y. 

10.  California  Hydraulic  Cement,  South  Riverside,  Cal. 

11.  Fort  Scott  Hydraulic  Cement,  "Brockett,"  Kansas  City,  Mo. 

12.  Utica  Hydraulic  Cement,  La  Salle,  111. 

13.  Shepherdstown  Hydraulic  Cement,  Shepherdstown,  Va. 

14.  Howard  Hydraulic  Cement,  Cement,  Ga. 

15.  Mankato  Hydraulic  Cement,  Mankato,  Minn. 

16.  James  River  Hydraulic  Cement,  Balcony  Falls,  Va. 


102  BUILDING  CONSTRUCTION. 

113.  Characteristics  of  Natural  Cement.  —Color.  The  color 
of  the  natural  cements  used  in  this  country  vary  with  the  locality  in 
which  they  are  found.  Most  of  the  cements  mentioned  in  Section 
in  are  brown  in  color,  in  light  or  dark  shades.  "In  Rosendale 
cement  a  light  color  generally  indicates  an  inferior,  underburnt  rock. 

"The  weight  of  good  Rosendale  cement  varies  from  49  to  56 
pounds  per  cubic  foot,  or  60  to  70  pounds  per  bushel,  according  to 
its  .fineness  and  the  density  of  packing.  The  harder-burned  varieties 
are  also  heavier  than  those  that  are  underburned.  The^weight  per 
barrel  of  Ulster  County  Rosendale  cement  averages  300  pounds  net  ; 
Akron,  Milwaukee,  Utica  and  Louisville  cements  weigh  265  pounds 
per  barrel  net." 

Testing  Rosendale  Cement. — The  value  of  cements  for 
making  mortar  varies  greatly  with  their  physical  properties,  and 
since  one  lot  is  liable  to  differ  very  much  from  another  lot  of  the 
same  brand,  it  is  very  necessary  to  be  able  to  test  the  character  of 
any  particular  cement. 

Brand. — Any  particular  brand  of  cement  will  generally  average 
about  the  same  strength  and  quality,  and  the  architect  should  ascer- 
tain what  brands  of  cement  are  giving  the  best  satisfaction  and  spec- 
ify those  brands.  For  ordinary  building  purposes  it  will  only  be  nec- 
essary for  the  superintendent  to  examine  the  casks  to  see  that  they 
bear  the  brand  specified  and  to  see  that  the  cement  has  not  been 
injured  by  dampness.  If  the  cement  is  found  to  have  become  hard 
or  crusty,  it  has  absorbed  moisture  and  should  not  be  used  in  making 
the  mortar. 

If  the  superintendent  has  any  doubts  of  the  quality  of  the  cement. 
let  him  take  two  handfuls  of  cement  and  mix  with  as  little  water  as 
possible  into  two  cakes  ;  put  one  in  water  and  leave  the  other  in  air. 
If  the  air  cake  dries  of  a  light  color  without  any  particular  well- 
defined  cracks,  and  the  water  cake  sets  with  a  darker  color  and  with- 
out cracks,  the  cement  is  probably  good.  If  the  cement  cracks  badly 
in  setting,  or  if  it  becomes  contorted  (sometimes  called  blowing),  it  is 
positively  poor  and  should  be  rejected. 

Another  simple  test  of  the  Soundness  of  cement,  which  is  the  prop- 
erty of  not  expanding  or  contracting,  or  checking  or  cracking  in  set- 
ting, is  to  place  some  mortar  in  a  glass  tube  (a  swelled  lamp  chimney 
is  excellent  for  this  purpose)  and  pour  water  on  top.  If  the  tube 
breaks  the  cement  is  unfit  for  use  in  damp  places.  Any  natural 
cements  that  give  satisfactory  results  with  these  simple  tests  will 
answer  for  making  mortar  for  any  ordinary  building  construction. 


LIMES,  CEMENTS  AND  MORTARS.  103 

Where  great  strength  is  required  in  the  mortar  it  is  better  to  use 
Portland  cement,  but  if  for  any  reason  Portland  cement  cannot  be 
tbtamed,  or  its  price  prohibits  its  use,  then  the  strength  of  the  natural 
cement  should  be  carefully  tested,  in  the  manner  described  in  Sec- 
tions 117-123  for  testing  Portland  cement. 

Clear  Rosendale  cement  one  week  old  in  water  should  have  a 
tensile  strength  per  square  inch  of  at  least  60  pounds,  and  the  best 
brands  should  average  100  pounds. 

Storing. — It  is  very  essential  that  cements  of  all. kinds  should  be 
stored  in  a  dry  place,  where  there  is  no  danger  of  its  absorbing  mois- 
ture, until  it  can  be  used.  A  very  little  moisture  will  cause  the 
cement  to  set,  and  any  cement  that  has  commenced  to  set  should  be 
rejected. 

114.  Roman   Cement  is  made  by  calcining  nodules  found  in 
the  London  clay.     The  color  of  the  calcined  stone  is  generally  a  rich 
brown. 

Weight  and  Strength.—"  Good  Roman  cement  should  not  weigh 
more  than  75  pounds  per  bushel,  and  should  set  very  quickly  (within 
about  fifteen  minutes  of  being  gauged  into  paste)."  A  heavier  cement 
than  this  is  likely  to  be  overburnt  or  else  injured  by  the  absorption 
of  carbonic  acid  from  the  air. 

Neat  Roman  cement  seven  days  old  in  water  should  possef  s  a  ten- 
sile strength  of  from  50  to  80  pounds  per  square  inch. 

Storing. — Roman  cement  is  sold  in  a  ground  state  and  is  put  up  in 
casks,  which  must  be  kept  carefully  closed  and  dry,  otherwise  the 
cement  will  absorb  carbonic  acid  and  become  inert. 
•  Uses. — The  strength  of  Roman  cement  diminishes  rapidly  when 
mixed  with  sand,  and  not  more  than  i  or  i^  parts  of  sand  to  i  of 
cement  should  be  used  in  mixing  the  mortar.  Roman  cement  mor- 
tar should  be  mixed  in  very  small  quantities  and  used  at  once,  and 
on  no  account  beaten  up  again  after  the  setting  has  commenced. 

ARTIFICIAL  CEMENTS. 

115.  Portland  Cement. — The  most  useful  of  artificial  cements 
is  that  known  as  Portland  cement. 

The  first  Portland  cement  was  made  by  Joseph  Aspdin,  of  Leeds, 
England,  who  obtained  a  patent  on  it,  dated  October  21,  1824.  For 
making  his  cement  he  used  powdered  limestone  and  a  certain  quan- 
tity of  clay,  which  he  mixed  together  with  water  to  a  paste,  then 
evaporated  in  pans.  After  evaporation  the  mixture  was  broken  up 
into  lumps,  calcined  at  a  high  temperature  and  ground. 


io4  BUILDING  CONSTRUCTION. 

The  name  of  Portland  was  given  to  the  cement  on  account  of  the 
fact  that  when  troweled  to  a  smooth  surface  it  resembled  rubbed 
Portland  stone,  one  of  the  chief  building  stones  of  England. 

"  Portland  cement  requires  a  homogeneous  mixture  containing  in 
proper  proportions  carbonate  of  lime,  alumina  (clay),  silica  and 
iron.  .  .  .  This  mixture  must  be 'subjected  to  a  heat  sufficiently 
high  to  produce  a  vitrified,  dense  and  heavy  clinker,  and  afterward 
ground  to  a  fine  powder." 

The  proper  proportions  of  the  above  ingredients  are  rarely  found 
in  a  natural  stone,  so  that  it  is  necessary  to  obtain  the  lime  and 
alumina  from  separate  sources  and  mix  them  in  the  proper  propor- 
tions artificially. 

At  the  present  time  the  bulk  of  the  English  cement,  and  much  of 
the  German  cement,  is  manufactured  from  chalk  instead  of  the  hard 
limestones.  This  chalk  is  mixed  with  clay  in  the  proper  proportions, 
before  burning,  in  a  large  wash  mill,  and  the  slurry  is  then  run  off 
and  dried,  either  by  artificial  means  or  sun  evaporation.  After  dry- 
ing the  mixture  is  burned  at  a  fixed  temperature  into  a  scoriaceous 
mass,  resembling  pumice  stone,  to  which  the  name  of  "clinker"  is 
applied.  This  "  clinker  "  being  dried,  ground  to  powder  and  passed 
through  sieves,  furnishes  the  finished  product. 

The  quality  of  the  cement  depends  upon  the  quality  of  the  raw 
materials,  the  proper  proportion  of  the  mixture,  the  degree  to  which 
it  is  burnt,  the  fineness  to  which  it  is  ground,  and  constant  and  scien- 
tific supervision  of  all  the  details  of  manufacture. 

Ii6.  American  Portland  Cement.— The  first  American  Port- 
land cement  was  manufactured  by  Mr.  David  O.  Saylor  in  the  year 
1874  at  Coplay,  Pa.  Since  that  time  several  factories  have  been 
established  in  the  United  States,  and  in  the  year  1894  there  were 
nineteen  factories,  which  made  about  700,000  barrels  ;  this  amount, 
however,  being  but  18  per  cent,  of  what  was  imported.  Most  of  the 
American  Portland  cement  is  manufactured  in  the  neighborhood  of 
Coplay,  Pa.,  the  largest  factory  being  that  of  the  Atlas  Cement  Co., 
where  1,800  barrels  a  day  are  now  manufactured.  "All  the  fac- 
tories located  in  this  region  make  cement  under  the  dry  process  from 
an  argillaceous  limestone.  There  are  several  factories  in  New  York 
State,  along  the  Erie  Canal,  and  in  Ohio,  where  marl  and  clay  or 
limestone  and  clay  are  used.  Practically  nine-tenths  of  the  Port- 
land cement  manufactured  in  this  country  is  made  in  the  States 
of  Pennsylvania,  New  York  and  Ohio.  Other  States  where  small 
quantities  are  manufactured  are  Texas,  Colorado,  Dakota,  Oregon, 
California  and  the  Territory  of  Utah.  There  is  plenty  of  raw  material' 


LIMES,  CEMENTS  AND  MORTARS.  105 

suitable  for  making  the  highest  grade  of  Portland  cement,  in  almost 
every  State  in  the  Union."* 

Several  of  the  American  Portland  cements  have  been  shown  by 
thousands  of  carefully  conducted  tests  to  be  equal  in  quality  to  any 
of  the  imported  cements,  and  they  have  been  used  with  perfectly  sat- 
isfactory results  in  many  of  the  largest  engineering  works  in  this 
country,  as  well  as  many  of  our  largest  buildings.  The  Mississippi 
jetties  were  built  with  American  Portland  cement,  and  they  have  suc- 
cessfully withstood  the  most  severe  test  to  which  cement  concrete  can 
be  subjected. 

Good  Portland  cement  is  slow-setting,  as  compared  with  the  natural 
cements,  but  greatly  surpasses  them  in  ultimate  strength. 

"  The  induration,  or  '  setting,'  of  Portland  cement  consists  in  the 
formation  of  a  real  mineral  of  a  crystalline  rock  species,  analogous  to 
natural  zeolites." 

Owing  to  the  greater  expense  in  manufacturing  Portland  cement, 
its  market  price  is  nearly  three  times  that  of  the  Rosendale  cements, 
but  where  great  strength  is  required,  as  in  brick  or  stone  piers,  or  for 
concrete  footings,  Portland  cement  should  always  be  preferred  to  any 
of  the  natural  cements. 

117.  Testing  Portland  Cement. — In  all  important  engineer- 
ing works  it  is  customary  to  test  every  fifth  or  tenth  cask  of  cement 
for  its  soundness,  fineness  and  strength. 

For  use  in  building  piers  and  footings  for  ordinary  buildings,  it 
will  be  sufficient  if  the  superintendent  sees  that  only  brands  bearing 
a  good  reputation  are  used  and  that  none  of  the  cement  has  com- 
menced to  set  or  crust  in  the  casks.  Any  such  cement  should  be 
rejected. 

In  places  where  great  strength  and  durability  is  required  of  the 
mortar  careful  tests  should  be  made  of  every  lot  of  cement  used,  as 
one  lot  of  cement  may  differ  very  much  from  another  lot  of  the  same 
brand. 

118.  Color. — Some  idea  of  the  quality  of  the  cement  may  be 
gained  from  its  color,  but  it  should  be  supplemented  by  further  tests 
for  strength  and  fineness,  as  a  bad  cement  may  be  of  good  color. 
Good  Portland  cement,  as  received  from  the  manufacturers,  should 
be  of  a  gray  or  bluish  gray  color. 

A  brown  or  earthy  color  indicates  an  excess  of  clay  and  shows  that 
the  cement  is  inferior — likely  to  shrink  and  disintegrate.  A  coarse, 


*  William  G.  Hartranft,  before  the  Master  Builders'  Exchange  of  Philadelphia 


io6  BUILDING  CONSTRUCTION. 

bluish-gray  powder  is  probably  over-limed  and  likely  to  blow.  An 
undue  proportion  of  underburnt  material  is  generally  indicated  by  a 
yellowish  shade. 

Weight. — The  weight  of  Portland  cement  is  sometimes  specified 
as  one  of  the  requirements  to  be  fulfilled,  but  as  it  is  never  constant, 
and  cannot  be  precisely  determined,  it  is  of  very  little  service  in 
determining  the  value  of  a  cement. 

The  finer  a  cement  is  ground  the  more  bulky  it  becomes,  and,  con- 
sequently, the  less  it  weighs  ;  a  ligrjt-burned  cement  also  weighs  less 
than  one  that  is  harder  burned,  so  that  light  weight  may  indicate 
either  a  desirable  fine  grinding  or  an  objectionable  underburning. 

The  weight  of  cement  should  be  determined  by  sifting  the  cement 
into  a  measure  with  a  fall  of  3  feet  and  striking  the  top  level  with  a 
straight-edge.  The  following  values  determined  in  this  way  give  fair 
averages  for  ordinary  cements: 

Portland,  English  and  German 77  to  90  Ibs.  per  cubic  foot. 

Portland,  fine  ground  French 69    " 

Portland,  American 95    " 

Roman 54    " 

Rosendale 49  to  56    " 

A  bushel  contains  practically  \\  cubic  feet,  so  that  the  weight  per 
bushel  can  be  easily  computed  from  the  above  table,  if  desired. 

119.  Activity.  —A  mortar  is  said  to  have  set  when  it  has  attained 
such  a  degree  of  hardness  that  it  cannot  be  altered  without  causing  a 
fracture,  i.  e.,  when  it  has  entirely  lost  its  plasticity.  Some  cements 
set  quickly,  while  others  are  comparatively  slow.  A  quick-setting 
cement  is  especially  valuable  in  constructions  under  water. 

Test  of  Activity. — To  test  hydraulic  activity  mix  cement  with  just 
enough  clean  water,  at  a  temperature  of  from  65°  to  70°  F.,  to  make. 
a  stiff  paste  and  make  one  or  two  cakes  or  pats  2  or  3  inches  in  diam- 
eter and  about  |  inch  thick.  As  soon  as  the  cakes  are  prepared, 
immerse  in  water  at  65°  F.  and  note  the  time  required  for  them  to 
set  hard  enough  to  bear  a  ^-inch  wire  loaded  to  weigh  \  pound  and 
4  pounds,  respectively.  "  When  the  cement  bears  the  light  weight  it 
is  said  to  have  begun  to  set ;  when  it  bears  the  heavy  weight  it  is  said 
to  have  entirely  set.  Cements,  however,  will  increase  in  hardness 
long  after  they  can  just  bear  the  heavy  wire.  The  activity  of  the 
cement  is  measured  by  the  time  which  elapses  between  the  time  when 
the  first  weight  is  supported  and  that  when  the  second  is  just  borne." 
An  increase  of  temperature  will  cause  the  cement  to  set  quicker 


LIMES,  CEMENTS  AND  MORTARS.  107 

while  cold  retards  it.     As  a  rule  Portland  cements  should  support  the 
heavy  wire  in  from  two  to  five  hours. 

120.  Soundness. — Tests  for  the  soundness  of  Portland  cement 
should  be  made  in  the  same  way  as  described  in  Section  113  for  tests 
of  Rosendale  cement.     The  color  of  the  cake  dried  in  the  air  should 
be  uniform  bluish    gray  throughout,  yellowish  blotches  indicating 
poor  cement.     The  cake  left  in  the  water  should  be  made  with  thin 
edges,  and,  if  at  the  end  of  twenty-four  hours  it  shows  fine  cracks 
around  the  edges,  it  is  unsafe  to  use  in  damp  places,  but  if  there  are 
no  cracks  it  may  be  considered  safe.     This  is  a  very  simple  test  to 
make,  and  should  be  made  in  all  cases  vhere  the  cement  is  to  be 
used  under  water. 

121.  Fineness. — There  is  no  doubt  that  properly  burnt  cement, 
when   ground   extremely   fine,  is,   as  compared  with    one    coarsely 
ground,  much  stronger  when  used  with  sand,  as  the  finer  the  parti- 
cles the  better  they  can  surround  the  cand  and  aggregates,  thus  more 
strongly   cementing   them  together.     The  finely  ground  cement  is 
also  the  safest  to  use.     The  hard-burnt  cements,  finely  ground,  make 
the  strongest  mortars. 

Measuring  Fineness. — "  The  degree  of  fineness  of  a  cement  is 
determined  by  measuring  the  per  cent,  which  will  not  pass  through 
sieves  of  a  certain  number  of  meshes  per  square  inch."  A  cement 
that  will  pass  through  a  sieve  of  2,500  meshes  (No.  35  wire  gauge) 
with  only  5  to  10  per  cent,  residue  is  sufficiently  fine  for  any  build- 
ing construction. 

122.  Strength. — The  most  important  test  of  cement  is  that  of 
its  strength.     This  is  generally  made  by  testing  the  tensile  strength 
of  the  cement  either  neat  or  mixed  with  sand.     Although  cement 
mortar  is  generally  subject  only  to  a  compressive  strain,  its  resistance 
to  compression  is  so  much  greater  than  to  tension  that  in  most  cases 
of  the  failure  of  mortar  it  is  broken  by  tensile  stress. 

Briquettes. — The  method  of  testing  the  tensile  strength  of  cement 
or  mortar  is  to  form  a  cake  or  brick  of  the  cement  or  mortar 
in  a  mould,  and  after  a  certain  limit  of  time  it  is  pulled  apart  and  the 
force  required  for  producing  fracture  carefully  noted.  Figs.  57  and 
58  show  the  shape  of  the  briquette  and  the  clamps  for  holding,  as 
recommended  by  the  Committee  of  the  American  Society  of  Civil 
Engineers. 

The  Machine. — There  are  many  machines  for  sale,  made  especially 
for  testing  the  strength  of  cement.  Fig.  59,  from  Baker's  "Treatise 
on  Masonry  Construction,"  represents  a  cement-testing  machine  that 


I08  BUILDING  CONSTRUCTION. 

can  be  made  by  an  ordinary  mechanic  at  small  expense.  It  is  not  as 
convenient  nor  quite  as  accurate  as  the  more  elaborate  machines,  but 
it  is  sufficiently  accurate  for  all  practical  purposes.  "  The  machine 


Fig.  58. 


consists  essentially  of  a  counterpoised  wooden  lever,  10  feet  long, 
working  on  a  horizontal  pin,  between  two  broad  uprights,  20  inches 
from  one  end.  Along  the  top  of  the  long  arm  runs  a  grooved  wheel 
carrying  a  weight,  W.  The  distances  from  the  fulcrum  in  feet  and 


Fig.  59- 


inches  are  marked  on  the  surface  of  the  lever,  and  also  the  corre- 
sponding effect  of  the  weight  at  each  point.  The  clamp,  C,  for  hold- 
ing the  briquette  is  suspended  from  the  short  arm,  18  inches  from 
the  fulcrum.  The  clamps  are  of  wood  and  are  fastened  by  clevis  joints 
to  the  lever  arm  and  bed  plate  respectively.  The  pin  is  iron  and  the 


LIMES,  CEMENTS  AND  MORTARS.  109 

*   > 

pin  holes  are  reinforced  by  iron  washers.  When  great  stresses  are 
required  extra  weights  are  hung  on  the  end  of  the  long  arm.  Pres- 
sures of  3,000  pounds  have  been  developed  with  this  machine." 

In  applying  the  load  on  the  briquette  it  is  recommended  that  it 
start  at  o  and  be  increased  regularly  at  the  rate  of  400  pounds  per 
minute  for  neat  Portland  cement,  and  200  pounds  per  minute  for 
natural  cements  and  mortar. 

A  rough  test  may  be  made  by  suspending  the  clamps  from  a  beam 
or  trestle  and  hanging  a  bucket  or  box  from  the  lower  clamp,  into 
which  sand  may  be  run  until  the  briquette  breaks,  and  the  weight 
then  weighed. 

123.  Mixing  the  Mortar. — Cements  should  be  tested,  both  neat 
and  mixed  with  sand.  Briquettes  made  entirely  of  cement  are  more 
convenient  for  testing,  as  they  may  be  tested  sooner,  and  there  can 
be  less  variation  in  the  mixture.  But  in  building,  cement  is  rarely 
used  without  an  admixture  of  sand,  and  the  most  valuable  compara- 
tive test  of  different  brands  submitted  would  be  to  make  the  bri- 
quettes of  cement  and  sand  such  as  is  to  be  used  in  the  mortar,  as 
while  one  cement  might  give  a  greater  strength  when  used  without 
sand,  when  mixed  with  the  sand  it  might  show  a  less  result  than 
another  brand,  owing  to  the  comparative  fineness  of  the  two. 

Practically  the  benefit  to  be  obtained  in  testing  the  strength  of 
cements  for  building  purposes  will  be  to  determine  which  of  the 
brands  that  are  available  are  the  most  desirable,  considering  both  the 
cost  and  the  strength,  although  where  a  certain  strength  is  specified 
the  cement  submitted  by  the  contractor  should  be  tested  to  see  if  it 
meets  the  requirements  of  the  specifications. 

In  comparing  different  brands  of  cement  great  care  should  be  used 
to  see  that  the  same  kind  and  quality  of  sand  is  used  in  each  case,  as 
difference  in  the  sand  might  cause  as  much  difference  in  the  results 
as  there  would  be  between  the  cements.  It  is  recommended  that  an 
average  of  at  least  five  briquettes  of  each  brand  of  cement  be  taken 
as  the  strength  of  the  cement. 

The  manner  of  making  the  briquettes  should  be  as  follows:  On  a 
thick  glass  plate  lay  sheets  of  blotting  paper  soaked  in  water,  and  on 
top  of  each  sheet  place  a  mould  wetted  with  water.  Before  mixing 
the  mortar  an  experimental  batch  should  be  made  to  determine  the 
exact  amount  of  water  required  to  mix  the  cement  to  the  proper  con- 
sistency. If  the  cement  is  mixed  with  sand,  both  the  cement  and 
the  dry  sand  should  be  carefully  weighed  to  get  the  desired  propor- 
tions, i  to  i  or  i  to  3,  as  desired,  and  the  sand  and  cement  thoroughly 


B  UILDING  CONS TR  UC TION. 


mixed  dry  in  a  tight  box.  All  the  water  required  for  mixing 
should  be  added  at  once,  and  the  whole  mass  thoroughly  and  rapidly 
mixed  for  five  minutes.  "With  the  mortar  so  obtained  the  moulds 
should  be  at  once  filled  with  one  filling,  so  high  as  to  be  rounded  on 
top,  the  mortar  being  well  pressed  in.  The  projecting  mortar  should 
then  be  pounded  with  a  trowel,  first  gently  and  from  the  side,  then 
harder  into  the  moulds,  until  the  mortar  grows  elastic  and  water 
flushes  to  the  surface.  A  pounding  of  at  least  one  minute  is  essen- 
tial. The  mass  projecting  over  the  mould  should  now  be  cut  off  with 
a  knife  and  the  surface  smoothed."  The  briquettes  should  be  removed 
from  the  moulds  as  soon  as  they  are  hard  enough  to  stand  it  without 
breaking,  and  should  be  placed  in  a  box  lined  with  zinc  and  provided 
with  a  cover.  The  briquettes  should  remain  in  the  box  twenty-four 
hours,  after  which  they  should  be  placed  under  water,  to  remain  until 
tested.  They  should  be  constantly  covered  with  water  until  tested, 
which  should  be  done  as  soon  as  they  are  taken  from  the  water. 

Age  of  Briquette  for  Testing. — Half  of  the  briquettes  are  generally 
tested  at  the  end  of  seven  days,  and  the  remainder  at  the  end  of 
twenty-eight  days.  If  it  is  impracticable  to  wait  twenty-eight  days  they 
may  be  tested  at  the  end  of  one  and  seven  days  respectively,  and  the 
ultimate  strength  of  the  cement  judged  by  the  increase  in  strength 
between  the  two  dates.  When  sand  is  used  in  making  the  briquettes 
it  is  desirable  to  wait  until  the  briquettes  are  twenty-eight  days  old. 

124.  Data  on  Strength.— Table  VIII.,  from  the  report  of  the  Com- 
mittee of  the  American  Society  of  Civil  Engineers  on  Uniform 
Tests  of  Cements,  gives  the  results  of  the  average  minimum  and  max- 
imum tensile  strength  per  square  inch  which  some  good  cements  have 
attained  when  tested  under  the  conditions  above  described. 

TABLE  VI1I.—TENSILE  STRENGTH  OF  CEMENT  MORTARS. 


AV.   TENSILE   STRENGTH 

AGE  OF   MORTAR  WHEN  TESTED. 

IN  POUNDS  PER  SQ.   INCH. 

PORTLAND. 

ROSENDALE. 

Clear  cement. 

Min. 

Max. 

Min. 

Max. 

i  day—  i  hour,  or  until  set,  in  air,  the  remainder  of  the  time  in  water, 
i  week—  i  day  in  air,  remainder  of  the  time  in  water     .  . 
4  weeks-i  day  in  air,  remainder  of  the  time  in  water  

35° 

140 
55° 
700 

40 

60 

80 

100 

150 

/  part  cement  to  I,  fart  sand 

45» 

800 

300 

400 

i  week—  i  day  in  air,  remainder  of  the  time  in  water... 
4  weeks—  i  day  in  air,  remainder  of  the  time  in  water 

30 

5° 

i  year—  i  day  in  air,  remainder  of  the  time  in  water 

.... 

/  part  Cement  to  3  parts  sand. 

300 

i  week—  i  day  in  air,  remainder  of  the  time  in  water 
4  weeks—  i  day  in  air,  remainder  of  the  time  in  water 
j  year—  i  day  in  air,  remainder  of  the  time  in  water 

80 

100 

"5 
35° 

.... 

:::: 

LIMES,  CEMENTS  AND  MORTARS.  in 

The  quantities  in  the  "  Min."  columns  give  the  average  strength 
of  the  weaker  brands  of  Portland  and  Rosendale  cements,  and  those 
in  the  "Max."  columns  the  average  strength  for  the  stronger  brands. 
By  comparing  his  results  with  the  values  in  this  table,  the  architect 
or  superintendent  can  judge  whether  his  cement  is  satisfactory  or  not. 

Limit  to  Increase  of  Strength  with  Age. — From  a  series  of  experi- 
ments made  by  Mr.  Grant  in  England  with  a  heavy  cement,  he  was 
led  to  the  conclusion  that  it  attained  its  maximum  strength  after  con- 
stant immersion  for  two  years,  and  that  there  is  no  reason  to  fear  that 
a  good  cement  ever  deteriorates.  With  a  light  cement  the  maximum 
strength  would  probably  be  attained  much  sooner. 

125.  Specifications    for    Cement. — In    works    where    it    is 
important  to  have  a  first-class  cement  the  specifications  should  read 
about  as  follows,  and  all  brands  submitted  should  be  carefully  tested, 
and  those  which  do  not  meet  the  requirements  should  be  rejected: 

Specification. — The  whole  of  the  cement  shall  be  Portland  cement 
of  the  very -best  quality,  weighing  not  less  than  no  pounds  to  the 
striked  bushel,  ground  so  fine  that  not  over  10  per  cent,  will  be 
rejected  by  a  sieve  of  2,500  meshes  per  square  inch  (No.  35  wire) 
and  capable  of  maintaining  a  breaking  weight  of  350  pounds  per 
square  inch  after  hardening  one  day  in  air  and  six  days  in  water, 
and  shall  show  no  cracks  or  blotches  when  left  under  water  twenty- 
four  hours. 

Any  cement  that  will  fulfill  these  requirements  should  be  good 
enough  for  any  building  construction  or  foundation. 

126.  Lafarge  Cement. — This  is  a  patented  preparation  of  cement 
similar  in  character  to  Portland  cement,  made  from  a  limestone  of 
hydraulic  properties.     It  is  hydraulic  in  character,  but,  unlike  Port- 
land or  Rosendale  cement,  does  not  stain  marble,  limestone  and  other 
porous  stones  when  used  in  setting  them,  and  therefore  is  especially 
desirable  for  setting  such  stones. 

For  setting  large  stones  mix  i  part  by  volume  of  lime  paste  to  4 
parts  of  the  cement,  to  retard  the  setting  of  the  cement  until  the 
stones  are  well  bedded. 

CEMENT  MORTARS. 

127.  Use. — Cement  mortar  should  be  used  for  all  mason  work 
below  grade,  or  where  situated  in  damp  places,  also  for  heavily  loaded 
piers  and  in  arches  of  large  span.     It  should  be  used  for  setting  cop- 
ing stones,  and  wherever  the  mason  work  is  especially  exposed  to  thj> 
weather. 


II2  BUILDING  CONSTRUCTION. 

For  construction  under  water,  and  in  heavy  stone  piers  or  arches, 
and  for  concrete,  Portland  cement  should  be  used:  elsewhere  natural 
or  Rosendale  cement  mortar  will  answer. 

128.  Mixing  the  Mortar. — For  use  in  ordinary  masonry  cement 
mortar  should  be  mixed  about  as  follows:  Spread  about  half  the  sand 
required  for  mixing  evenl,  over  the  bed  of  the  mortar  box  (which 
should  be  water  tight),  and  then  spread  the  dry  cement  evenly  over 
the  sand  and  spread  the  remaining  sand  on  top.     Thoroughly  mix 
the  dry  sand  and  cement  with  a  hoe  or  shovel,  as  this  is  a  very  essen- 
tial part  of  the  process.     The  dry  mixture  should  be  shoveled  to  one 
end  of  the  box  and  water  poured  into  the  other  end.     "  Cements  vary 
greatly  in  their  capacity  for  water,  freshly-ground  cements  requiring 
more  than  those  that  have  become  stale.     An  excess  of  water  is, 
however,  better  than  a  deficiency,  particularly  when  a  very  energetic 
cement  is  used,  as  the  capacity  of  this  substance  for  absorbing  water 
is  great."     The  sand  and  cement  should  then  be  drawn  down  with  a 
hoe  in  small  quantities  and  mixed  with  the  water  until  enough  has 
been  added  to  make  a  good  stiff  mortar,  care  being  taken  not  to  get 
it  too  thin.     This  should  be  vigorously  worked  with  a  hoe  for  five 
minutes  to  get  a  thorough  mixture.     The  mortar  should  leave  the  hoe 
clean  when  drawn  out  of  it,  very  little  sticking  to  the  steel.     But  a 
very  small  quantity  of  cement  mortar  should  be  mixed  at  a  time,  par- 
ticularly that  made  of  Rosendale  cements,  as  the  cement  soon  com- 
mences to  set,  after  which  it  should  not  be  used.     As  a  rule  natural 
cement  mortars  should  not  be  used  after  they  have  been  mixed  two 
hours,  and  Portland  cement  mortars  after  four  hours  (for  best  work 
not  over  one  hour). 

The  sand  and  cement  should  not  be  mixed  so  as  to  stand  over 
night,  as  the  moisture  in  the  sand  will  destroy  the  setting  qualities 
of  the  cement. 

Should  be  Kept  Moist. — "  Hydraulic  cements  set  better  and  attain 
a  greater  strength  under  water  than  in  the  open  air  ;  in  the  latter, 
owing  to  the  evaporation  of  the  water,  the  mortar  is  liable  to  dry 
instead  of  setting.  This  difference  is  very  marked  in  hot,  dry 
weather.  If  cement  mortar  is  to  be  exposed  to  the  air  it  should  be 
shielded  from  the  direct  rays  of  the  sun  and  kept  moist." 

129.  Proportion  of  Sand. — "  A  paste  of  good  hydraulic  cement 
hardens  simultaneously  and  uniformly  throughout  the  mass,  and  its 
strength  is  impaired  by  any  addition  of  sand."     As  mortar  is  never 
used  by  itself,  however,  but  as  a  binding  material  for  brick  and  stone, 
and  there  can  obviously  be  no  advantage  in  making  the  strength  of 


LIMES,  CEMENTS  AND  MORTARS.  113 

the  mortar  joints  greater  than  that  of  the  bricks  or  stones  they  unite, 
sand  is  always  added  to  the  cement  in  making  mortar.  As  cement  is 
much  more  expensive  than  sand,  the  larger  the  proportion  of  sand  in 
the  mortar  the  less  will  be  its  cost.  The  proportion  of  sand  should 
vary  according  to  the  kind  of  cement  and  the  kind  of  work  for  which 
the  mortar  is  to  be  used.  For  natural  cements  the  proportion  of  sand 
to  cement  by  measurement  should  not  exceed  3  to  i,  and  for  piers  and 
first-class  work  2  to  i  should  be  used.  Portland  cement  mortar  may 
contain  4  parts  of  sand  to  i  of  cement  for  ordinary  mortar,  and  3  to 
i  for  first-class  mortar.  For  work  underwater  not  more  than  2  parts 
of  sand  to  i  of  cement  should  be  used.  When  cheaper  mortars  than 
these  are  desired  it  will  be  better  to  add  lime  to  the  mortar  instead 
of  more  sand. 

Plastering  mortar,  for  stucco  work  or  waterproofing,  should  be 
made  of  i  part  cement  and  i  part  sand.  For  lining  cisterns  2  parts 
of  natural  cement  or  i  of  Portland  cement  should  be  used. 

The  following  table  shows  the  comparative  strength  of  English 
Portland  cement  mortar,  with  different  proportions  of  sand  and  at 
different  ages: 


AGE    AND    TIME 
IMMERSED. 

PROPORTION   OF   CLEAN   PIT   SAND  TO    I   CEMENT. 

Neat 
cement. 

i  to  i. 

2  to  I. 

3  to  i. 

4  to  i. 

5  to  i. 

445-0 
679-9 
877-9 
978.7 
995-9 
1,075-7 

152.0 
326.5 
549-6 
639-2 
718.7 
795-9 

64-5 
166-5 
451-9 

497-9 
594-4 
607.5 

44-5 
91-5 
305-3 
304-0 
383.6 
424.4 

22.0 

71-5 

153-0 
275-6 

317.6 

49.0 
123-5 

218.8 

215.6 

Twelve  months  

P.  177,  "  Notes  on  Building  Construction,"  Part  III. 

The  values  in  the  table  represent  the  breaking  strength  in  pounds 
on  a  sectional  area  of  2^  square  inches.  The  superintendent  should 
see  that  the  cement  and  sand  for  each  batch  of  mortar  are  carefully 
measured  to  get  the  right  proportions. 

130.  Portland  and  Rosendale  Cement,  Mixed. — Whenever 
a  quick-setting  cement  is  desired,  which  shall  attain  a  greater 
strength  than  the  natural  cements,  a  mixture  of  Portland  and  natural 
cement  may  be  used.  "  Such  mortar  sets  about  as  quickly  as  if  made 
with  natural  cement  alone,  and  acquires  great  subsequent  strength, 
due  to  the  Portland  cement  contained  in  it.  The  strength  of  the 


ii4  BUILDING  CONSTRUCTION. 

mixed  mortar  is  almost  exactly  a  mean  between  that  of  the  two  mor- 
tars separate." 

131.  Lime  with  Cement. — An  economical  and  strong  mortar 
for  use  in  dry  places  may  be  made  by  mixing  Rosendale  cement  with 
lime  mortar,  in  the  proportion  of  i  part  of  cement  to  4  parts  of  lime 
mortar.     The  lime  mortar  should  be  well  worked  and  the  lime  thor- 
oughly slaked  before  the  cement  is  added,  and  only  a  small  quantity  of 
the  cement  and  lime  mortar  should  be  made  up  at  a  time.     Such  a 
mortar  has  a  strength  which  is  about  a  mean  between  that  of  lime 
mortar  and  Rosendale  cement  mortar,  and  which  is  amply  sufficient 
for  ordinary  brickwork.     Portland  cement,  mixed  with  lime  mortar 
in  the  above  proportion,  gives  no  better  results  than  good  Rosendale 
cement.     It  is  better  to  use  a  small  proportion  of  lime  with  cement 
mortar  than  to  use  too  large  a  proportion  of  sand,  as  the  latter  makes 
the  mortar  porous  and  liable  to  disintegrate  rapidly.     In  England  a 
mixture  of  Portland  cement  and  lime  mortar  appears  to  be  much 
used.     Lime  should  not  be  added  to  cement  mortar  when  it  is  to  be 
used  in  wet  places. 

132.  Grout  is  a  very  thin  liquid  mortar  sometimes  poured  over 
courses  of  masonry  or  brickwork  in  order  that  it  may  penetrate  into 
empty  joints  left  in  consequence  of  bad  workmanship.     It  is  also 
sometimes  necessary  to  use  it  in  deep  and  narrow  joints  between 
large  stones.     Its  use  is  not  generally  recommended  by  writers  on 
mortars,  and  the  writer  believes  that  it  should  not  be  used  in  stone- 
work where  it  can  be  avoided.     For  brickwork,  however,  the  author 
feels  convinced  that  walls  grouted  with  a  moderately  thin  mortar 
every  course  makes  a  solid  job.     If  the  bricks  are  well  wet  before  lay- 
ing, and  every  joint  slushed  full  of  stiff  mortar,  it  is  impossible  to  get 
anything  stronger  ;  but  in  most  localities  it  is  difficult  to  get  such  work 
without  keeping  an  inspector  constantly  on  the  ground,  and  when  the 
walls  are  grouted  the  joints  are  sure  to  be  filled.     In  his  own  prac- 
tice the  author  always  specifies  grouting  for  all  brick  footings  and 
foundation  walls.     Many  of  the  largest  buildings  in  New  York  City 
have  grouted  walls. 

133.  Data  for  Estimates. — The  following  memoranda,  made  up 
from  data  given  by  Prof.  Baker,  will  be  found  useful  in  estimating 
the  amounts  of  materials  required  in  making  any  given  quantity  of 
mortar: 

Lime  Mortar.— A  barrel  of  lime   weighs   about    230   pounds  ;  a 
bushel  of  lime,  75  pounds.     One  barrel  (or  three  bushels)  of  lime  and 


LIMES,  CEMENTS  AND  MORTARS.  115 

I  yard  of  sand  will  make  i  yard  of  i  to  3  lime  mortar,  and  will  lay 
about  80  cubic  feet  of  rough  brickwork  or  common  rubble. 

Cement  Mortar. — 1.8  barrels,  or  540  pounds,  of  natural  cement 
and  .94  cubic  yards  of  sand  will  make  i  cubic  yard  of  i  to  3  mortar; 
two  barrels,  or  675  pounds,  of  Portland  cement  and  .94  cubic  yaid 
of  sand  will  also  make  i  cubic  yard  of  i  to  3  mortar  ;  1.7  barrels,  or 
525  pounds,  of  Portland  cement  and  .98  cubic  yard  of  sand  will  make 
i  cubic  yard  of  i  to  4  mortar ;  i  cubic  yard  of  mortar  will  lay  from 
67  to  80  cubic  feet  of  rough  rubble  or  brickwork,  from  90  to  108 
cubic  feet  of  brickwork  with  f  to  £-inch  joints,  and  from  324  to  378 
cubic  feet  of  stone  ashlar. 

A  cubic  foot  of  common  brickwork  contains  about  eighteen  bricks. 

134.  Strength  of  Mortar. — The  exact  strength  of  mortar  to  resist 
compression  is  not  of  very  great  importance,  as  it  seldom,  if  ever, 
fails  in  this  way.     The  tensile  and   adhesive  strength  of  mortar  is 
more  important,  particularly  the  latter,  as  whenever  a  building  has 
fallen  from  using  poor  mortar  it  has  generally  been  on  account  of  the 
failure  of  the  mortar  to  adhere  to  the  bricks  or  stones.     Whatever 
kind  of  mortar  is  used,  it  should  be  made  rich  and  well  worked,  as 
the  saving  by  using  more  sand  is  but  a  small  percentage  at  most,  and 
it  is  never  safe  for  an  architect  to  allow  poor  mortar  to  be  used  in  his 
buildings. 

The  safe  crushing  strength  of  Portland,  Rosendale  and  lime  mor- 
tars used  in  ^-inch  joints  should  equal  the  following  values  in  tons 
per  square  foot: 

Portland  cement  mortar,  I  to  3,  3  months,    40  tons;  i  year,  65  tons. 

Rosendale    "  "         I  to  3,  3  months,    13  tons;  I  year,  26  tons. 

Lime  mortar,  i  to  3,  3  months,  8.6  tons;  I  year,  15  tons. 

From  these  values  we  see  that  for  granite  piers,  heavily  loaded, 
only  Portland  cement  mortar  should  be  used.  For  all  piers  loaded 
with  over  10  tons  per  square  foot,  and  not  exceeding  20  tons,  Rosen- 
dale  cement  mortar  should  be  used.  Lime  mortar  should  never  be 
used  for  piers  that  are  to  receive  their  full  load  within  six  months. 

135.  "  The  adhesion  of  mortars  to  brick  or  stone  varies  greatly 
with  the  different  varieties  of  'these  materials,  and  particularly  with 
their  porosity.     The    adhesion  varies  also  with  the  quality  of   the 
cement,  the  character,  grain  and  quantity  of  the  sand,  the  amount  of 
water  used  in  tempering,  the  amount  of  moisture  in  the  stone  or 
brick,  and  the  age  of  the  mortar." 

Mortar  adheres  to  both  stone  and  brick  better  when  they  are  wet 
(unless  the  temperature  is  below  the  freezing  point),  and  the  architect 


n6  BUILDING  CONSTRUCTION. 

should  always  insist  on  having  the  bricks  well  wet  down  with  a  hose 
before  laying.  A  dry  brick  absorbs  the  moisture  from  the  mortar  so 
that  it  cannot  harden  properly  and  destroys  its  adhesive  properties. 
The  wetting  of  the  brick  is  fully  of  as  much  importance  as  the  quality 
of  the  mortar  in  brickwork.  The  adhesive  strength  of  the  cements 
and  lime  are  as  a  rule  in  proportion  to  their  tensile  strength.  There- 
fore where  great  adhesive  strength  is  desired  to  prevent  sliding,  as  in 
arches,  etc.,  either  Portland  or  Rosendale  cement  should  be  used, 
according  to  the  importance  of  the  work  and  stress  to  be  resisted. 
Some  years  ago  the  walls  of  a  brick  building  in  New  York  City  were 
pushed  outward  by  barrels  of  flour  piled  against  the  walls,  so  that  the 
walls  suddenly  fell  into  the  street.  An  examination  of  the  mortar 
showed  that  it  was  of  poor  quality,  with  little  adhesion  to  the  bricks. 
Had  good  mortar  been  used  and  the  brick  well  wet,  the  failure  (it 
should  not  be  called  an  accident)  would  not  have  occurred.  The 
adhesive  and  tensile  strength  of  mortar  is  also  of  great  importance  in 
resisting  wind  pressure  and  vibration. 

136.  Mortar  Impervious  to  Water. — A  frequent  case  of  the  failure 
of  masonry  is  the  disintegration  of  the  mortar  in  the  outside  of  the 
joints,  although  this  does  not  take  place  to  such  an  extent  in  build- 
ings as  in  engineering   works.     "  Ordinary  mortar — either  lime  or 
cement — absorbs  water  freely,  common  lime  mortar  absorbing  from 
50  to  60  per  cent,  of  its  own  weight,  and  the  best  Portland  cement 
mortar  from   10  to  20  per  cent.,  and  consequently  they  disintegrate 
under  the  action  of  the  frost.     Mortar  may  be  made  practically  non- 
absorbent  by  the  addition  of  alum  and  potash  soap.     One  per  cent., 
by  weight,  of  powdered  alum  is  added  to  the  dry  cement  and  sand 
and  thoroughly  mixed,  and  about   i   per  cent,  of  any  potash   soap 
(ordinary  soft  soap  made  from  wood  ashes  is  very  good)  is  dissolved 
in  the  water  used  in  making  the  mortar.     The  alum  and  soap  com- 
bine and  form  compounds  which  are  insoluble  in  water.     These  com- 
pounds are  not  acted  upon  by  the  carbonic  acid  of  the  air,  and  add 
considerable  to  the  early  strength  of  the  mortar  and  somewhat  to  its 
ultimate  strength."*     The  alum  and  soap  are  comparatively  cheap 
and  can  be  easily  used. 

The  mixture  could  be  advantageously  used  in  plastering  basement 
walls  and  on  the  outside  of  buildings,  and  would  add  greatly  to  the 
durability  of  mortar  used  for  pointing. 

137.  Plaster  of  Paris  in  Mortar. — Plaster  of  Paris,  which  is  sul- 
phate of  lime,   when   added  to  either  lime   or   cement   mortar   in 

*"  Treatise  on  Masonry  Construction,"  Bak^r. 


LIMES,  CEMENTS  AND  MORTARS.  117 

quantities  not  exceeding  5  per  cent.,  accelerates  the  setting  and  also 
increases  the  early  and  the  ultimate  strength  of  mortar.  Lime  mor- 
tar to  which  plaster  of  Paris  has  been  added  is  called  gauged  mortar. 
Selenetic  cement,  an  artificial  cement  much  used  in  England,  is  made 
by  combining  plaster  of  Paris  and  hydraulic  lime,  in  the  proportion 
of  three  pints  of  the  plaster  to  a  bushel  of  unslaked  lime.  The  addi- 
tion of  the  plaster  of  Paris  to  lime  appears  to  increase  the  strength  of 
the  mortar  from  two  to  three  times. 

138.  Sugar  in  Mortar. — Sugar  has  been  employed  for  centuries  in 
India  as  an  ingredient  of  common  lime  mortar,  and  adds  greatly  to 
the  strength  of  the  mortar. 

An  addition  of  sugar  or  syrup  equal  to  one-tenth  of  the  weight  of 
the  unslaked  lime,  to  lime  mortar,  adds  50  per  cent,  to  the  strength 
•of  the  mortar  and  will  cause  the  mortar  to  set  more  quickly.  The 
addition  of  sugar  to  lime  mortar  is  especially  beneficial  when  used  in 
very  thick  walls,  as  the  lime  mortar  thus  placed  never  becomes  fully 
saturated  with  carbonic  acid. 

Sugar  added  to  Rosendale  and  Portland  cement  mortars  in  the  pro- 
portion of  ^  to  £  per  cent,  in  weight  of  the  cement,  increases  the 
•strength  of  the  mortars  about  25  per  cent. 

As  the  combination  of  sugar  and  lime  is  soluble  in  water,  sugar 
should  not  be  added  to  mortar  that  is  to  be  used  under  water. 

139.  Freezing  of  Mortar. — Freezing   does  not  appear  to  injure 
lime  mortar  if  the  mortar  remains  frozen  until  it  has  fully  set.     Alter- 
nate freezing  and  thawing  materially  damages  the  strength  and  adhe- 
sion of  lime  mortar,  and  as  this  is  generally  what  happens  when  mor- 
tar is  laid  in  freezing  weather,  it  is  much  the  safest  rule  for  the  archi- 
tect to  specify  and  see  that  no  masonry  shall  be  laid  with  lime  mortar 
in  freezing  weather.     "  Mortar  composed  of  i  part  Portland  cement 
and  3  parts  of  sand  is  entirely  uninjured  by  freezing  and  thawing, 
mortar  made  of  cements  of  the  Rosendale  type,  in  any  proportion,  is 
entirely  ruined  by  freezing  and  thawing."* 

Salt  in  Mortar. — When  it  is  desired  to  use  natural  cement  mortar 
in  freezing  weather  the  mortar  should  be  mixed  with  water  to  which 
•salt  has  been  added  in  the  proportion  of  one  pound  of  salt  to  eighteen 
gallons  of  water,  when  the  temperature  is  at  32°  F.,  and  for  each 
degree  of  temperature  below  32°  add  three  additional  ounces  of  salt. 
Mortar  mixed  with  such  a  solution  does  not  freeze  in  ordinary  winter 
weather,  and  hence  is  not  injured  by  frost. 


'Trans.  Am.  Soc.  of  C.  E.,  Vol.  XVI.,  pp.  79-84. 


u8  BUILDING  CONSTRUCTION. 

When  masonry  must  be  laid  in  freezing  weather  the  bricks  or  stones 
should  be  warmed  sufficiently  to  thaw  off  any  ice  upon  their  surface  or 
in  the  pores  of  the  bricks  before  being  laid. 

Builders  sometimes  advocate  the  addition  of  lime  to  Rosendale 
cement  mortar  in  cold  weather  to  warm  it.  The  heating  effect  of  the 
lime,  however,  would  not  be  appreciable,  as  heat  is  generated  in  lime 
only  when  it  slakes.  If  cement  of  the  Rosendale  type  must  be  used 
in  freezing  weather,  the  only  safe  way  of  using  it  is  by  the  addition 
of  salt,  as  described  above,  otherwise  the  mortar  will  be  completely 
ruined  by  freezing. 

Change  of  Volume  in  Setting. — Cement  mortars  diminish 
slightly  in  volume  in  setting  in  air  and  expand  when  under  water, 
but  the  expansion  and  contraction  is  not  sufficient  to  injuriously 
affect  building  construction. 

CONCRETE. 

140.  There  is  probably  no  material  that  is  so  enduring,  or  better 
adapted  for  foundations  (and  also  walls,  vaults,  etc.),  than  cement 
concrete,  and  perhaps  none  that  is  so  much  "skimped." 

Concrete  may  be  defined  as  an  artificial  rock,  made  by  uniting 
sand,  broken  stone,  gravel,  fragments  of  brick,  pottery,  etc.,  by  means 
of  lime  or  cement. 

Concrete  made  with  lime,  however,  is  not  suitable  for  damp  situa- 
tions, and  even  when  used  for  walls  above  ground  it  is  much  better 
to  use  either  a  "Portland"  or  "natural"  cement  for  the  uniting 
material. 

Concrete  made  with  good  Portland  cement,  in  proper  proportions, 
becomes  so  hard  and  strong  that  when  pieces  of  the  concrete  are 
broken  the  line  of  fracture  will  often  be  found  to  pass  through  the 
particles  of  stone,  showing  that  the  adhesion  of  the  cement  to  the 
stone  is  greater  than  the  strength  of  the  stone. 

For  the  aggregates  no  material  is  better  than  clean,  freshly  broken 
stone,  in  size  about  as  large  as  a  hen's  egg.  Granite  probably  makes 
the  best  aggregates,  but  other  hard  stones  will  answer  for  any  ordi- 
nary concrete.  Soft  sandstones  or  "  freestones  "  are  not  desirable. 
Pieces  of  hard  brick  or  dense  terra  cotta  also  make  good  aggregates. 

Whatever  material  is  used  it  is  essential  that  it  be  free  from  dirt 
and  that  the  particles  be  clean. 

Good  clean,  coarse  gravel  is  also  extensively  used  for  the  mass  of 
the  concrete,  and  some  architects  and  builders  prefer  it  to  broken 
stone,  but  as  all  gravel  has  more  or  less  rounded  and  smooth  surfaces, 


LIMES,  CEMENTS  AND  MORTARS.  119 

it  would  seem  as  though  the  cement  must  adhere  more  firmly  to 
angular  and  broken  surfaces. 

A  certain  proportion  of  clean,  coarse  sand  is  also  required  to  fill 
the  voids  between  the  particles  of  stone  or  gravel. 

The  method  of  making  and  using  concrete  is  very  simple,  but 
owing  to  the  fact  that  it  is  impossible  to  tell  from  an  examination  of 
the  product  the  amount  of  cement  that  has  been  used,  and  the  great 
temptation  to  the  contractor  to  use  as  little  cement  as  possible,  not 
more  than  one-half  or  two-thirds  of  the  amount  of  cement  specified 
is  generally  used  (unless  an  inspector  is  kept  on  the  work),  and  the 
mixing  of  the  materials  is  also  often  very  imperfectly  done. 

141.  Measuring  the   Materials. — The  only  proper  way  to 
make  concrete  is  by  carefully  measuring  the  proportions  of  cement, 
sand,  broken  stone,  etc.     This  may  readily  be  done  by  using  the 
common  mason's  wheelbarrow  for  a  unit  of  measure  and  mixing 
together  the  specified  number  of  barrows  of  each  material. 

For  ordinary  building  operations,  where  the  concrete  is  mixed  by 
hand,  as  much  concrete  as  may  be  made  by  two  barrows  of  cement 
is  all  that  can  be  worked  at  one  time  to  advantage.  The  ordinary 
barrel  of  cement  will  just  about  fill  two  barrows,  so  that  one  barrel  of 
cement  may  be  considered  as  equal  to  two  barrows,  or  parts.  If  the 
proportion  is  specified  in  this  way,  however,  the  inspector  should 
have  a  barrel  emptied  into  two  barrows,  and  then  permit  the  barrows 
to  be  filled  with  the  sand  and  gravel  only  to  the  extent  that  they  are 
filled  by  the  cement. 

142.  Manner   of  Mixing. — The  most  satisfactory  method  of 
mixing  concrete  by  hand  is  to  first  prepare  a  tight  floor  of  plank,  or, 
better  still,  of  sheet  iron  with  the  edges  turned  up  about  2  inches,  for 
mixing  the  materials  on. 

Upon  this  platform  should  first  be  spread  the  sand,  and  upon  this 
the  cement.  The  two  should  then  be  thoroughly  and  immediately 
mixed  by  means  of  shovels  or  hoes,  and  the  broken  stone  or  aggre- 
gates then  dumped  on  top  and  the  whole  worked  over  dry  with 
shovels,  and  then  worked  over  again  while  water  is  added  from  a 
sprinkler  on  the  end  of  a  hose.  Only  as  much  water  should  be  added 
as  is  necessary  to  cause  the  cement  to  completely  coat  and  cause  to 
adhere  all  the  particles  of  the  aggregates.  Too  much  water  will 
lessen  the  strength  of  the  concrete. 

The  water  used  should  be  clean  and  at  about  the  temperature  of  65°. 

There  are  many  machines  for  mixing  mortar,  which,  for  large 
quantities  of  concrete,  effect  a  saving  in  the  cost  of  mixing,  and 


120 


BUILDING  CONSTRUCTION. 


probably  do  the  work  more  thoroughly  and  evenly.  As  soon  as  the 
concrete  is  mixed  it  should  be  wheeled  to  the  trenches  in  barrows 
and  dumped. 

Instead  of  first  mixing  the  cement  and  sand,  very  good  results  may 
be  obtained,  with  perhaps  a  little  less  labor,  by  depositing  the  broken 
stone  on  the  sand  after  it  is  spread  over  the  platform,  and  then  the 
cement  on  top  of  the  stone,  and  working  the  whole  over  dry  with 
shovels.  The  first  method,  however,  is  to  be  preferred  where  an 
extra  quality  of  concrete  is  desired. 

143.  Proportions. — The  best  proportion  of  cement,  sand  and 
aggregates  will  depend  upon  the  kind  and  quality  of  the  cement  used 
and  the  character  of  the  work. 

The  proportion  of  sand  to  aggregates  should  be  such  that  the  sand 
will  just  fill  the  voids  in  the  aggregates.  This  will,  of  course,  vary 
with  the  size  of  the  aggregates  and  the  coarseness  of  the  sand.  For 
stone  broken  to  go  through  a  2|-inch  ring,  about  one-half  as  much 
sand  as  stone  is  required,  on  an  average,  to  fill  the  voids.  After  one 
batch  of  concrete  has  been  deposited  and  rammed  the  inspector  can 
generally  tell  by  the  appearance  whether  too  much  or  too  little  sand 
has  been  used. 

Natural  Cement  Concrete. — For  concrete  foundations  under  build- 
ings of  moderate  height,  and  for  foundations  for  cement  pavements, 
natural  cements  make  as  strong  concrete  as  is  required. 

For  the  best  brands  of  natural  cements  i  part  cement,  2  parts  sand 
and  4  parts  gravel  or  broken  stone  should  be  used. 

[This  proportion  was  used  in  the  foundations  of  the  Brooklyn 
Bridge.] 

Portland  Cement  Concrete. — For  concrete  to  be  used  under  heavy 
buildings  and  under  water  Portland  cement  should  be  used. 

For  the  best  brands  of  cement  2  parts  of  cement  to  5  of  sand  and 
9  of  broken  stone  will  answer  for  almost  any  building  construction. 
Much  larger  proportions  of  sand  and  aggregates  than  these  are  often 
used,  but  the  author  would  not  recommend  a  greater  proportion  than 
the  above  unless  the  quality  of  the  cement  is  constantly  tested  and 
only  the  best  used,  and  the  concrete  mixed  under  rigid  inspection. 

144.  Examples   of  Portland   Cement   Concrete.— Foundations    of 
Mutual    Life   Insurance   Company's  Building,  New  York:    i    part 
cement,  3  parts  sand,  5  parts  broken  stone. 

Foundation  of  U.  S.  Naval  Observatory :  i  part  cement,  2^  sand, 
3  gravel,  5  broken  stone,  [i  barrel  of  cement,  380  pounds,  made 
1.18  yards  of  concrete.] 


LIMES,  CEMENTS  AND  MORTARS.  121 

Foundations  of  Cathedral  of  St.  John  the  Divine,  New  York:  13,000 
cubic  yards  of  concrete  have  been  used  in  the  foundation  of  the  tower 
and  choir,  the  average  depth  being  15  feet.  Proportions  :  i  part  Port- 
land cement,  2  parts  sand,  3  parts  quartz  gravel,  i^  to  2  inches  in 
diameter. 

Filling  of  caissons,  Johnston  Building  (fifteen  stones)  New  York  : 
i  part  Portland  cement,  3  parts  sand,  7  parts  stone,  finished  on  top 
for  brickwork  with  i  part  cement  and  3  parts  gravel. 

Manhattan  Life  Insurance  Building,  New  York,  filling  of  caissons: 
i  part  Alsen  Portland  cement,  2  parts  sand,  4  parts  broken  stone. 

The  proportion  of  cement  is  sometimes  specified  as  "  one  barrel 
of  cement  to  a  yard  of  concrete,"  but  as  it  is  very  inconvenient  to 
measure  the  concrete  by  the  yard  such  a  specification  is  not  to  be 
recommended. 

145.  Depositing. — As  soon  as  a  batch  of  concrete  is  mixed  it 
should  be  wheeled  to  the  trenches  and  deposited  in  layers  from  6  to 
10  inches  in  thickness.     Where  the  total  thickness  of  concrete  does 
not  exceed  18  inches  the  layers  should  not  be  more  than  6  inches 
thick.     The  concrete  should  not  be  dumped  from  a  greater  height 
than  4  feet  above  the  bottom  of  the  trench.     If  dumped  from  a  greater 
height  the  heavy  particles  are  apt  to  separate  from  the  lighter  ones. 

As  soon  as  a  square  yard  of  concrete  has  been  deposited  it  should 
be  tamped  with  a  wooden  rammer  weighing  about  20  pounds.  The 
tamping  should  be  sufficient  to  just  flush  the  water  to  the  surface. 
The  concrete  should  not  be  permitted  to  dry  too  quickly,  and  if 
twenty-four  hours  elapse  between  depositing  the  successive  layers  the 
top  of  each  layer  should  be  sprinkled  before  the  next  is  deposited. 

146.  Strength  of  Concrete.— The  writer  is  not  acquainted  with 
any  reliable  tests  on  the  compressive  strength  of  concrete,  but  it  is 
generally  assumed  that  the  strength  of  thoroughly  mixed  concrete  is 
equal  to  that  of  mortar  made  of  the  same  proportions  of  sand  and 
cement.     The  crushing  strength  of  6-inch  cubes  of  i  to  2  Portland 
cement  mortar  was  found  by  tests  made  at  the  Watertown  Arsenal  to 
average  about  500  pounds  per  square  inch,  or  36  tons  per  square  foot. 
For  the  working  strength  of  concrete  the  author  recommends  the  fol- 
lowing values,  the  larger  values  being  for  work  done  under  strict 
inspection  with  the  best  of  cement : 

Portland  cement  concrete,  i  to  8,  8  to  20  tons  per  square  foot ; 
natural  cement  concrete,  i  to  6,  5  to  10  tons  per  square  foot. 

The  estimated  weight  to  be  imposed  on  the  concrete  footings  of 
the  Cathedral  of  St.  John  the  Divine  is  10  tons  per  square  foot. 


J22  BUILDING  CONSTRUCTION, 

147.  Data  for  Estimating.— There  seem  to  be  few  records  of 
careful  measurements  of  the  amount  of  materials  required  to  make  a 
cubic  yard  of  concrete,  but  the  following  data  is  believed  to  be  rea- 
sonably accurate : 

Used  in  the  proportion  of  i  part  cement,  3  of  sand  and  5  of  broken 
stone,  in  sizes  not  exceeding  2x1^x3  inches,  one  barrel  of  cement 
will  make  from  22  to  26  cubic  feet  of  concrete,  the  average  being 
about  23  cubic  feet. 

In  putting  in  the  foundations  of  the  Cathedral  of  St.  John  the 
Divine,  New  York,  it  required  17,000  barrels  of  Portland  cement  to 
make  11,000  yards,  or  about  one  and  one-half  barrels  to  the  yard. 
The  proportions  were  i,  2  and  3. 

Concrete  made  of  i  part  cement,  2^  of  sand,  3  of  gravel  and  5  of 
broken  stone  gave  1.18  yards  of  concrete  to  a  barrel  of  cement. 

The  ordinary  cement  barrel  contains  about  3^  cubic  feet. 

At  $2  a  day  for  labor,  the  cost  of  mixing  and  depositing  concrete 
should  not  exceed  $i  a  cubic  yard.  The  cost  per  yard  of  Portland 
cement  concrete  will  generally  vary  from  $6  to  $8,  according  to  the 
cost  of  the  cement,  labor  and  aggregates. 

MORTAR  COLORS  AND  STAINS. 

148.  The  use  of  artificial  coloring  in  mortars  has  been  in  vogue, 
more  or  less,  for  two  thousand  years,  but  the  general  use  of  colored 
mortars  dates  from  a  comparatively  recent  period. 

The  object  aimed  at  in  using  colored  mortars  is  either  to  get  the 
effect  of  a  mass  of  color,  by  concealing  the  joints,  or  else,  by  using 
a  contrasting  color,  to  emphasize  the  joints.  Rougher  bricks  may 
also  be  used  with  nearly  as  good  effect  by  using  a  mortar  of  the  same 
color  as  the  bricks.  Chipped  or  uneven  edges  do  not  show  as  plainly 
with  mortar  of  the  same  color  as  the  bricks  as  they  do  when  laid  with 
white  mortar. 

Objections  to  Mortar  Colors.— The  objection  is  sometimes  made  to 
the  use  of  colored  mortars  that  they  are  not  as  strong  as  white  mor- 
tars and  that  the  color  is  very  apt  to  fade. 

These  objections  undoubtedly  have  much  truth  in  them  when 
cheap  colors  are  used  and  the  mortar  is  not  properly  mixed,  but  it  is 
very  doubtful  if  the  better  grades  of  mortar  colors  now  on  the  market 
affect  the  strength  of  the  mortar  to  any  appreciable  extent,  and  when 
properly  mixed  with  lime  putty  they  seldom,  if  ever,  fade. 

149.  Kinds  Of  Colors.  -Most,  if  not  all,  of  the  coloring  materials 
sold  under  the  name  of  "  mortar  colors,"  or  stains,  consist  of  mineral 


LIMES,  CEMENTS  AND  MORTARS.  123 

pigments  put  up  either  in  the  form  of  a  dry  powder  or  in  the  form 
of  a  pulp  or  paste. 

Pulp  colors  are  said  to  be  susceptible  of  more  uniform  mixing  with 
the  mortar  than  dry  colors,  and,  as  a  rule,  appear  to  have  the  prefer- 
ence for  the  better  grades  of  work. 

Paste  or  pulp  stains  should  not  be  allowed  to  freeze,  and  should  be 
kept  moist  by  covering  with  water. 

A  great  deal  of  colored  mortar  is  made  by  using  Venetian  red,  or 
the  cheap  grades  of  mineral  paints  for  the  coloring  matter.  The  ordi- 
nary Venetian  red  is  very  apt  to  fade  and  also  weakens  the  mortar, 
and  the  cheaper  grades  of  mineral  colors  are  not  much  better.  The 
cost  of  the  coloring  matter  is  so  small  an  item  that  only  the  very  best 
grades  should  be  used. 

Among  the  brands  of  mortar  colors  generally  recognized  as  belong- 
ing to  the  first  grade  are  the  "Clinton,"  "Peerless,"  "Pecora" 
"Edinburgh,"  " American  Seal,"  "Milwaukee'1  and  "Cabot" 

The  principal  colors  used  are  red,  brown,  buff  and  black,  although 
green,  purple,  gray  and  drab  mortar  colors  are  also  made. 

150.  Mixing. — Mortar  colors,  whether  in  dry  or  paste  form, 
should  not  be  mixed  with  lime  until  the  latter  has  been  slaked  at 
least  twenty-four  hours,  and  the  best  way  is  to  keep  a  lot  of  lime  putty 
on  hand  and  mix  the  color  with  it  as  needed. 

The  color  should  be  thoroughly  and  evenly  mixed  with  the  putty 
before  the  sand  is  added,  and  for  very  fine  work  the  colored  putty 
should  be  strained  through  a  coarse  sieve. 

For  cement  work  the  stain  should  be  thoroughly  mixed  with  the 
sand  or  gravel  and  set  aside  in  barrels,  and  the  cement  added  in 
small  quantities  as  required  for  use. 

Like  all  water  paints,  the  color  of  the  mortar  looks  different  in  the 
bed  than  when  dry.  To  get  the  final  color  of  the  mortar  a  little 
should  be  taken  from  the  bed  and  permitted  to  dry  thoroughly,  when 
the  permanent  color  may  be  seen. 

The  amount  of  coloring  matter  required  to  stain  a  given  quantity 
of  mortar  varies  with  the  different  colors  and  brands.  The  following 
quantities  may  be  taken  as  the  average  amounts  required  in  laying 
one  thousand  face  brick  : 

Red  or  terra  cotta,  50  pounds. 

Buff,  brown  or  French  gray,  25  pounds. 

Black,  22  pounds. 


CHAPTER  V. 
BUILDING  STONES. 


It  is  important  that  an  architect  should  have  some  knowledge  of 
the  nature  of  the  different  kinds  of  stone,  that  he  may  know  what 
stone  is  best  to  use  under  any  given  circumstances,  and  what  stones 
not  to  use.  It  can  hardly  be  expected  that  an  architect  shall  be  a 
geologist,  a  mineralogist  or  a  chemist,  and  thus  capable  of  determin- 
ing the  exact  composition  of  a  stone,  but  it  is  expected  of  him  that 
he  shall  know  enough  of  the  subject  to  specify  stones  that  shall  have 
sufficient  strength  and  durability  and  that  will  not  become  discolored 
through  chemical  changes  in  their  constituents. 

To  acquire  such  a  knowledge  of  building  stones  requires  not  only 
a  study  of  their  mineral  constituents  and  of  their  structure,  but  also 
accurate  observation  and  much  experience  with  stones. 

The  following  short  description  of  the  principal  building  stones  of 
this  country,  with  the  localities  in  which  they  are  quarried,  will  enable 
the  young  architect  to  get  some  idea  of  their  composition  and  char- 
acteristics, and,  it  is  hoped,  assist  him  in  making  a  judicious  selection 
of  stones  for  special  cases.*  The  stones  are  classed  according  to 
their  structure  and  composition. 

151.  Granite,  Gneiss  and  Syenite. — The  granites  are  massive 
rocks  occurring  most  frequently  as  the  central  portions  of  mountain 
chains.  They  are  a  hard,  granular  stone,  composed  principally  of 
quartz,  feldspar  and  mica,  in  varying  proportions.  When  the  stone 
contains  a  large  proportion  of  quartz  it  is  very  hard  and  difficult  to 
work.  When  there  is  a  considerable  proportion  of  feldspar  the  stone 
works  more  easily. 

The  color  of  the  granite  is  principally  determined  by  the  color  of 
the  feldspar,  but  the  stone  may  also  be  light  or  dark,  according  as  it 
contains  light  or  dark  mica.  The  usual  color  of  granite  is  either  a 
light  or  dark  gray,  although  all  shades  from  light  pink  to  red  are 
found  in  different  localities. 


*  For  a  complete  work  on  the  subject  the  reader  is  referred  to  "  Stones  for  Building  and  Dec- 
oration," by  George  P.  Merril,  Ph.D.;  John  Wiley  &  Sons,  publishers.  Much  valuable  infor. 
mation  relating  to  building  stones  may  also  be  found  in  the  various  numbers  of  Stone. 


BUILDING  STONES.  125 

The  light  fine-grained  stones  are  the  strongest  and  most  durable, 
although  almost  every  granite  has  sufficient  strength  for  ordinary 
building  construction.  It  generally  breaks  with  regularity  and  may 
be  readily  quarried,  but  it  is  extremely  hard  and  tough  and  works 
with  great  difficulty,  so  that  it  is  a  very  expensive  stone  to  use  for  cut 
work.  It  is  impossible  to  do  fine  carving  in  most  granites.  Granite  is 
one  of  the  best  stones  for  foundations,  base  courses,  water  tables,  etc., 
and  for  columns  and  all  places  where  great  strength  is  required;  also 
for  steps,  thresholds  and  for  flagging,  when  it  can  be  slit  readily. 

Excellent  varieties  of  granite  may  be  obtained  in  any  of  the  New- 
England  States  and  in  most  of  the  Southern  States  and  the  Rocky 
Mountain  region,  and  in  California  and  Minnesota. 

As  a  rule  granite  can  be  quarried  in  any  size  desired.  New  quar- 
ries should  be  analyzed  to  see  if  they  contain  iron,  in  which  case  it 
would  be  dangerous  to  use  the  stone  for  ornamental  purposes  until  its 
weathering  qualities  have  been  thoroughly  tested  by  exposing  blocks 
for  a  long  time  to  the  weather.  If  the  iron  is  a  sulphurate  it  is  quite 
sure  to  stain  the  stone. 

Gneiss  (pronounced  like  nice)  has  the  same  composition  as  granite, 
but  the  ingredients  are  arranged  in  more  or  less  parallel  layers.  On 
this  account  the  rock  split  in  such  a  way  as  to  give  parallel  flat  sur- 
faces, which  renders  the  stone  valuable  for  foundation  walls,  street 
paving  and  flagging.  Gneiss  is  generally  taken  for  granite,  and  is 
frequently  called  by  quarrymen  stratified  or  bastard  granite. 

Syenite  is  a  rock  also  resembling  granite,  but  containing  no  quartz. 
It  is  a  hard,  durable  stone,  generally  of  fine  grain  and  light  gray 
color.  The  principal  syenite  quarries  in  this  country  are  near  Little 
Rock,  Arkansas.* 

All  three  of  these  stones  are  badly  affected  by  fire,  large  pieces 
breaking  off  and  the  stone  cracking  badly. 

Fox  Island,  Me.;  Groton,  Conn.;  Woodstock,  Md.;  St.  Cloud,  Minn.,  and  Nova 
Scotia  granites  are  spoiled  at  900°  F.  Hallowell,  Me. ;  Red  Beach,  Me. ;  Oak  Hill, 
Me.,  and  Quincy,  Mass.,  granites  are  spoiled  at  1,000°  F.  The  granites  stand- 
ing the  highest  fire  tests  are:  Barre,  Vt. ;  Concord,  N.  H. ;  Ryegate,  Vt. ;  Mt. 
Desert,  Me. 


*  In  many  books  and  papers  treating  on  granite,  syenite  is  described  as  a  rock  consisting  of 
quartz,  feldspar  and  hornblende,  the  latter  taking  the  place  of  the  mica  in  the  true  granites. 
According  tc.  the  modern  methods  of  classification  such  rocks  are  called  "  hornblende  granite." 

"  The  name  '  syenite  '  takes  its  origin  from  Syene,  Egypt,  but  the  stone  from  which  it  was 
named  has  been  found  to  contain  more  mica  than  hornblende.  According  to  recent  lithologists. 
the  Syene  rock  is  a  hornblende,  mica  granite,  while  true  syenite,  as  above  stated,  is  a  quartzless 
rock."— Merrill. 


I26  BUILDING  CONSTRUCTION. 

152.  Description  of  some  of  the  best  known  Granites. 

Vinalhaven,  Fox  Island,  Afe. — These  quarries  are  the  most  extensive  in  the 
country ;  texture  of  stone  rather  coarse ;  color,  gray ;  contains  a  small  amount  of 
hornblende.  It  takes  a  good  and  lasting  polish,  and  is  well  adapted  for  all  manner 
of  ornamental  work  and  general  building  purposes.  The  stone  has  been  used  exten- 
sively all  over  the  country  for  both  building  and  monumental  purposes. 

Hallo-well,  Me. — This  stone  is  celebrated  for  its  beauty  and  fine  working  quali- 
ties, and  is  in  great  demand  for  monuments  and  statuary.  It  is  a  fine  light  gray 
rock,  comparatively  pure,  the  principal  constituents  being  quartz,  feldspar  and  mica. 
Has  been  used  extensively  all  over  the  country. 

There  are  many  other  quarries  of  fine  granite  in  Maine. 

Quincy,  A/ass. — The  Quincy  granite  quarries  are  amongst  the  oldest  in  the  coun- 
try. The  product  is,  as  a  rule,  dark  blue-gray  in  color,  coarse  grained  and  hard. 
Composition:  quartz,  hornblende  and  feldspar.  The  polished  stairways  and  pilas- 
ters in  the  new  City  Hall  at  Philadelphia  are  of  this  stone. 

Concord,  N.  H. — A  fine-grained  granite,  light  gray  color,  with  a  silver  lustre ; 
well-developed  rift  and  grain,  and  remarkable  for  the  ease  with  which  it  can  be 
worked.  Constituents:  opaque  quartz,  soda  feldspar  and  white  mica.  Well  adapted 
for  statuary  and  monumental  purposes,  as  well  as  for  general  building.  The  stone 
is  eminently  durable,  the  New  Hampshire  State  House,  built  of  this  stone  in  1816-19, 
being  still  in  an  excellent  state  of  preservation.  The  Congressional  Library  build- 
ing, Washington,  D.  C.,  is  built  of  this  stone. 

North  Con  way,  JV.  H. — A  coarse-grained  granite  ;  colors,  red  and  green,  the  red 
being  the  principal  variety.  Contains  both  hornblende  and  pyroxene.  Used  in  the 
Union  Depot,  Portland,  Me. 

Westerly,  R.  I. — Granite  of  fine  grain  and  even  texture  and  of  excellent  quality. 
Constituents:  quartz,  feldspar  and  mica,  with  some  hornblende.  Color,  rich  light 
gray  or  pink,  with  a  distinct  tint  of  brown  when  polished. 

Jonesborough,  Me.— At  this  place  is  quarried  a  pink  or  reddish  granite,  which  is 
generally  considered  as  the  best  American  red  granite  at  present  quarried.  The 
stone  is  very  compact  and  hard,  and  much  finer  in  texture  than  the  celebrated  red 
Scotch  granite. 

St.  Cloud,  Minn. — Both  gray  and  red  granites  are  quarried  at  this  place;  the  lat- 
ter greatly  resembles  the  Scotch  granite  in  color,  grain  and  polish.  The  gray  gran- 
ite is  about  one-third  quartz  and  two-thirds  feldspar. 

GranitevilU,  Mo. — Here  is  quarried  a  very  hard  red  granite,  mottled  with  gray 
and  black,  which  takes  a  handsome  polish.  The  stone  has  been  used  in  many 
important  buildings  in  St.  Louis,  Kansas  City  and  Chicago. 

Colorado. — This  Stale  also  contains  great  quantities  of  granite,  which,  however, 
have  been  but  little  developed.  The  principal  quarry  is  at.Gunnison,  which  pro- 
duces a  blue-gray  granite,  which  may  be  seen  in  the  Colorado  State  House. 

Georgia. — Excellent  grades  of  light  and  dark  gray  granite  are  contained  in  this 
State,  but  as  yet  they  are  developed  only  to  a  small  extent. 

153.  Limestone. — This  name  is  commonly  used  to  include  all 
stones  which  contain  lime,  though  differing  from  each  other  in  color, 
texture,  structure  and  origin.     All  limestones  used  for  building  pur- 
poses contain  one  or  more  of  the  following  substances,  in  addition  to 


BUILDING  STONES  127 

lime  :  Carbonate  of  magnesia,  iron,  silica,  clay,  bituminous  matter, 
mica,  talc  and  hornblende. 

There  are  three  varieties  of  limestone  used  for  building  purposes, 
viz.:  Oolitic  limestone,  magnesian  limestone  and  dolomite. 

Oolitic  limestones  are  made  up  of  small  rounded  grains  (resembling 
the  eggs  of  a  fish)  that  have  been  cemented  together  with  lime  to  form 
a  solid  rock. 

Magnesian  limestones  include  those  limestones  which  contain  loper 
cent,  and  over  of  carbonate  of  magnesia. 

Dolomite  is  a  crystalline  granular  aggregation  of  the  mineral  dolo- 
mite, and  is  usually  whitish  or  yellowish  in  color.  It  is  generally 
heavier  and  harder  than  limestone. 

All  varieties  of  limestone  are  liable  to  contain  shells,  corals  and 
fossils  of  marine  animals,  more  or  less  pulverized.  A  limestone  can 
be  identified  by  its  effervescence  when  treated  with  a  dilute  acid. 

Many  of  our  finest  building  stones  are  limestones,  but  as  they  are 
less  easily  and  accurately  worked  than  sandstones  they  are  not  so 
largely  used  except  in  the  localities  where  the  best  varieties  are 
found. 

The  color  of  limestone  is  generally  a  light  gray,  though  it  is  some- 
times a  deep  blue,  and  occasionally  of  a  cream  or  buff  color.  The 
light  gray  varieties  often  resemble  the  light,  fine-grained  granites  in 
appearance. 

Most  of  the  granular  limestones  are  susceptible  of  a  high  polish. 

Good  limestone  should  be  of  a  fine  grain  and  weigh  about  145 
pounds  per  cubic  foot. 

The  limestones  described  below  are  very  durable,  but  the  light- 
colored  stones  are  apt  to  become  badly  stained  in  large  cities,  and 
especially  in  those  cities  in  which  soft  coal  is  used. 

All  kinds  of  limestone  are  destroyed  by  fire,  although  some  varie- 
ties will  stand  a  greater  degree  of  heat  without  injury  than  others. 

154.  Description  of  Limestones. — The  limestones  most  exten- 
sively used  for  building  purposes  come  from  the  States  of  Illinois, 
Indiana,  Ohio,  New  York  and  Kentucky. 

The  most  celebrated  American  limestone  is  that  quarried  at  Bedford,  Indiana, 
which  is  a  light-colored  oolite,  consisting  of  shells  and  fragments  of  shells  (so  mi- 
nute as  to  be  scarcely  discernible  by  the  naked  eye),  cemented  together  by  carbonate 
of  lime. 

This  stone  is  most  remarkably  uniform  in  grain  and  texture,  is  exceedingly  bright 
and  handsome  in  color,  and  is  less  liable  to  discolor  than  most  light  stones. 

It  is  equally  strong  in  vertical,  diagonal  and  horizontal  directions,  and  when  first 
quarried  is  so  soft  as  to  be  readily  worked  with  a  saw  or  chisel ;  it  hardens,  however, 


128  BUILDING  CONSTRUCTION. 

on  exposure,  and  attains  a  strength  of  10,000  to  12,000  pounds  per  square  inch. 
Owing  to  its  fine  and  even  grain  and  ease  in  cutting  in  any  direction,  it  is  especially 
adapted  for  fine  earring.  The  stone  is  also  very  durable. 

On  account  of  its  many  excellent  qualities  it  was  selected  by  the  architect  for  Mr. 
George  W.  Vanderbilt's  palatial  residence  at  Biltmore,  N.  C.  The  Auditorium 
Building  at  Chicago,  the  Manhattan  Life  Building,  New  York  ;  the  mansion  of  Mr. 
C.  J.  Vanderbilt  on  Fifth  Avenue,  New  York  ;  the  State  House  at  Indianapolis  and 
many  other  prominent  buildings  are  built  of  this  stone.  There  are  several  quarries 
of  this  stone,  the  products  varying  somewhat  in  color  and  quality. 

A  gray  limestone  is  quarried  at  Lockport,  N.  Y.,  which  is  extensively  used  for 
trimmings  in  that  State  and  some  parts  of  New  England. 

There  are  large  quarries  of  limestone  at  Dayton  and  Sandusky,  Ohio ;  Joliet, 
Grafton  and  Chester,  Illinois,  and  in  the  vicinity  of  Topeka,  Kansas.  There  are 
several  small  quarries  which  supply  the  local  demand  in  various  parts  of  Kansas. 
The  Topeka  stone  can  be  worked  almost  as  easily  as  wood,  and  yet  becomes  hard 
and  durable  when  placed  in  the  building. 

At  Carthage,  Jasper  County,  Missouri,  there  are  extensive  quarries  of  limestone, 
which  produce  large  quantities  both  of  quicklime  and  building  stone.  The  stone  is 
coarse  grained  and  crystalline,  takes  a  good  polish,  and  is  well  adapted  to  exterior 
finishing. 

Excellent  quarries  of  limestone  also  exist  at  Phoenix,  Missouri,  the  stone  being 
shipped  to  St.  Louis,  Kansas  City  and  Omaha. 

Kentucky. — This  State  also  contains  a  great  quantity  of  fine  limestone,  some  varie- 
ties of  which  are  said  to  be  equal,  if.  not  superior,  to  the  Bedford  stone.  The  best 
known  of  the  Kentucky  limestones  is  probably  the  Bowling  Green  (oolitic)  stone, 
quarried  at  Memphis  Junction.  This  stone  is  almost  identical  in  composition  with 
the  celebrated  "  Portland  "  stone  of  Great  Britain.  Its  color  is  light  gray.  It  is  as 
readily  worked  as  the  Bedford  stone,  is  very  durable,  and  is  pre-eminent  in  its  resist- 
ance to  the  discoloring  influences  of  mortar,  cement  and  soil. 

MARBLE. 

155.  Marble  is  simply  a  crystallized  limestone,  capable  of  taking  a 
good  polish. 

The  scarcity  and  consequent  expense  of  good  marbles  have  in  the 
past  prevented  them  from  being  used  in  constructional  work,  except 
occasionally  for  columns.  Most  of  the  marbles  obtained  from  the 
older  quarries  also  stain  so  easily  that  they  are  considered  undesir- 
able for  exterior  work. 

Since  the  rapid  development  of  the  Georgia  and  Tennessee  mar- 
ble quarries,  however,  stone  from  these  quarries  has  been  much  used 
for  exterior  finish,  and  even  for  the  entire  facing  of  the  walls.  These 
marbles  will  probably  be  more  extensively  used  for  exterior  work  in 
the  future,  as  they  are  exceedingly  strong  and  durable  and  do  not 
stain  readily. 

Nearly  all  varieties  of  marble  work  comparatively  easy,  and  the 
fine-grained  varieties  are  especially  adapted  for  fine  carving. 


BUILDING  STONES. 


129 


They  generally  resist  frost  and  moisture  well,  and  are  admirably 
suited  for  interior  decoration,  sanitary  purposes,  etc.,  and  in  clear, 
dry  climates  make  a  splendid  material  for  exterior  construction. 

The  strength  of  marble  varies  from  5,000  to  20,000  pounds  per 
square  inch,  and  only  when  used  for  columns  need  its  strength  be 
considered. 

[For  the  composition  and  strength  of  various  marbles  see  tables  in 
appendix.] 

156.  Description  of  Leading  American  Marbles. — Great 
quantities  of  white  and  black  marble  are  quarried  in  this  country, 
but  nearly  all  of  the  beautiful  streaked  and  colored  marbles  are 
imported. 

The  States  which  produced  marble  in  1894  were  California, 
Georgia,  Idaho,  Maryland,  New  York,  Oregon,  Pennsylvania,  Ten- 
nessee and  Vermont. 

Vermont  Marble. — This  State  is  the  greatest  producer  of  marble  of  any  State  in 
the  Union,  the  total  product  in  1889  amounting  to  $2,169,560,  more  than  the  com- 
bined value  of  all  other  marbles  quarried  in  the  country. 

The  largest  quarries  are  at  West  Rutland  and  Sutherland  Falls  (Proctor). 

In  texture  Vermont  marble  is,  as  a  rule,  fine  grained,  although  some  of  it  is 
coarse  grained  and  friable.  In  color  it  varies  from  pure  snowy  white  through  all 
shades  of  bluish,  and  sometimes  greenish,  often  beautifully  mottled  and  veined,  to 
deep  blue-black;  the  bluish  and  dark  varieties  being,  as  a  rule,  the  finest  and  most 
durable. 

These  marbles  are  used  principally  for  monumental  and  statuary  work,  and  for 
decorative  work,  sanitary  fittings,  tiling,  etc. ,  in  buildings. 

At  Sutherland  Falls  the  stone  is  very  massive,  and  large  blocks  are  taken  out  for 
general  building  purposes. 

Tennessee. — Marble  has  been  quarried  in  this  State  since  1838,  the  principal  quar- 
ries being  in  the  vicinity  of  Knoxville,  in  East  Tennessee.  The  varieties  of  marble 
produced  from  these  quarries  embrace  grays,  light  pinks,  dark  pinks,  buffs,  choco- 
late and  drabs.  Only  the  pinks  and  grays,  however,  are  suitable  for  general  build- 
ing purposes,  the  darker  colors  being  principally  confined  to  furniture  and  interior 
work.  The  stone  is  98  per  cent,  carbonate  of  lime.  The  pink  and  gray  varieties  are 
well  adapted  for  building  purposes,  their  density  and  resistance  to  crushing  being 
equal  to  that  of  any  other  marble  produced  in  the  world. 

They  also  offer  great  resistance  to  moisture,  and  are  practically  impervious  to  the 
staining  or  discoloring  agencies  of  the  atmosphere,  except,  perhaps,  in  large  manu- 
facturing centres.  Under  favorable  conditions  there  appears  to  be  no  reason  why 
these  marbles  should  not  last  for  ages  on  the  exterior  of  buildings.  The  highly  col- 
ored varieties  are  amongst  the  handsomest  produced  in  this  country. 

Georgia. — This  State  contains  extensive  beds  of  marble,  which,  however,  have 
only  recently  been  quarried  on  a  commercial  scale.  The  quarries,  which  are  situated 
in  the  northern  part  of  the  State,  produce:  1st.  A  clear  white  marble,  bright  and 
sparkling  with  crystals.  2d.  A  dark  mottled  white  ground,  with  dark  blue  mot* 


I3o  BUILDING  CONSTRUCTION. 

tlings  ;  also  a  light  blue  and  gray  ground,  with  dark  mottlings.  3d.  White,  with 
dark  blue  spots  and  clouds,  and  a  bluish-gray,  with  dark  spots  and  clouds.  4th.  Pink, 
rose  tints  and  green  in  several  shades.  The  appearance  of  the  Georgia  marbles  is 
quite  different  from  that  of  the  marbles  from  the  other  States. 

The  stone  is  a  pure  carbonate  of  lime,  entirely  free  from  foreign  or  hurtful  ingre- 
dients. It  is  remarkably  non-absorbing,  and  absolutely  impervious  to  liquids  (even 
ink),  atmospheric  changes  and  decay,  and  not  subject  to  discoloration.  If  soiled  by 
dust  or  smoke  it  can  be  easily  cleaned  by  washing  with  clean  water  only  so  as  to  look 
as  bright  as  when  first  finished. 

Georgia  marble  has  been  extensively  used  for  monuments  and  for  the  interior  fin- 
ish of  buildings,  notably  in  the  new  Congressional  Library.  It  is  also  used  mere  and 
more  every  year  for  exterior  construction,  either  as  trimmings  or  for  the  entire  wall. 
It  may  be  seen  in  the  exterior  of  the  Ames  Building  at  Boston,  the  Equitable  Building 
at  Baltimore,  St.  Luke's  Hospital  at  New  York  and  many  other  prominent  buildings. 

New  York. — There  are  several  quarries  of  gray,  blue  and  white  marble  near  New 
York  City  which  furnish  good  building  marble,  but  not  quite  good  enough  for  dec- 
orative work.  Much  of  it  has  been  used  for  building  purposes  in  New  York  City. 

The  best  quality  of  black  marble  is  quarried  at  Glens  Falls,  on  the  Hudson  River. 
In  Montgomery  County,  Pennsylvania,  are  several  quarries  of  a  granular  white  and 
mottled  marble,  which  have  furnished  a  great  deal  of  marble  for  Philadelphia 
buildings. 

Colorado  and  California  also  contain  beautiful  varieties  of  marble,  which  it  is 
thought  may  in  time  take  the  place  of  much  of  the  foreign  marble  now  imported.  At 
present  only  a  very  few  quarries  are  worked,  and  these  only  to  a  slight  extent. 

157.  Onyx  Marble. — These  stones  are  of  the  same  composition 
as  common  marbles,  but  were  formed  by  chemical  deposits  instead 
of  in  sedimentary  beds,  crystallized  by  the  action  of  heat.  "They 
owe  their  banded  structure  and  variegated  colors  to  the  intermittent 
character  of  the  deposition  and  the  presence  or  absence  of  various 
impurities,  mainly  metallic  oxides.  The  term  onyx  as  commonly 
applied  is  a  misnomer,  and  has  been  given  merely  because  in  their 
banded  appearance  they  somewhat  resemble  the  true  onyx,  which  is 
a  variety  of  agate." 

Owing  to  their  translucency,  delicacy  and  variety  of  colors,  and 
the  readiness  with  which  they  can  be  worked  and  polished,  the  onyx 
marbles  are  considered  the  handsomest  of  all  building  stones,  and 
they  also  bring  the  highest  price,  the  cost  per  square  foot  for  slabs  i 
inch  thick  varying  from  $2.50  to  $6.  Their  use  is  confined  to  inte- 
rior decoration,  such  as  wainscoting,  mantels,  lavatories,  and  for 
small  columns,  table  tops,  etc.  Most  of  the  onyx  marble  used  in  the 
United  States  is  imported  from  Mexico,  although  considerable  onyx 
is  quarried  at  San  Luis  Obispo,  California,  and  quarries  of  very  beau- 
tiful stone  have  recently  been  opened  near  Prescott,  Arizona.  The 
Mexican  onyx  presents  a  great  variety  of  colors,  creamy  white,  amber 


BUILDING  STONES.  131 

yellow  and  light  green,  generally  more  or  less  streaked  or  blotched 
with  green  or  red.  Some  of  the  light  stones  have  a  beautiful  trans- 
lucent clouded  effect.  When  cut  across  the  grain  the  stone  often 
presents  a  beautifully  banded  structure  like  the  grain  of  wood.  Cut- 
ting the  stone  across  the  grain,  however,  greatly  weakens  its  strength, 
so  that  it  is  necessary  to  back  it  with  slabs  of  some  stronger  marble. 

The  San  Luis  Obispo  stone  is  nearly  white,  finely  banded,  trans- 
lucent, and  takes  a  beautiful  surface  and  polish. 

The  Arizona  stone  presents  a  greater  variety  of  coloring,  from 
milky  white  to  red,  green,  old  gold  and  brown,  intermingled  in  every 
possible  way.  But  a  comparatively  small  amount  of  this  stone  is  as 
yet  on  the  market,  but  further  developments  will  probably  result  in 
the  production  of  a  great  quantity  of  the  stone. 

158.  Sandstones. — "  Sandstones  are  composed  of  rounded  and 
angular  grains  of  sand  so  cemented  and  compacted  together  as  to 
form  a  solid  rock.  The  cementing  material  may  be  either  silica,  car- 
bonate of  lime,  an  iron  oxide  or  clayey  matter." 

They  include  some  of  the  most  beautiful  and  durable  stones  for 
exterior  construction,  and  on  account  of  the  ease  with  which  they 
can  be  worked  and  their  wide  distribution  throughout  the  country, 
are  more  extensively  used  for  exteriors  than  any  other  stone. 

The  grains  of  sand  themselves  are  nearly  the  same  in  all  sand- 
stones, being  generally  pure  quartz,  the  character  of  the  stone 
depending  principally  upon  the  cementing  material.  If  the  cement- 
ing material  is  composed  entirely  of  silica,  the  rock  is  light  colored 
and  generally  very  hard  and  difficult  to  work.  When  the  grains  have 
been  cemented  together  by  fusion  or  by  the  deposition  of  silica 
between  the  granules,  and  the  whole  hardened  under  pressure,  it  is 
almost  the  same  as  pure  quartz  and  is  called  quartzite — one  of  the 
strongest  and  most  durable  of  rocks.  "  If  the  cementing  material  is 
composed  largely  of  iron  oxides  the  stone  is  red  or  brownish  in  color 
and  usually  not  too  hard  to  work  readily.  WThen  the  cementing 
material  is  carbonate  of  lime  the  stone  is  light  colored  or  gray,  soft 
and  easy  to  work."  Such  stones  do  not  as  a  rule  weather  well,  a^  the 
cementing  material  becomes  dissolved  by  the  rain,  thereby  loosening 
the  grains  and  allowing  the  stone  to  disintegrate.  Clay  is  still  more 
objectionable  than  lime  as  a  cementing  material,  as  it  readily  absorbs 
water  and  renders  the  stone  liable  to  injury  by  frost. 

In  some  sandstones  part  of  the  grains  consist  of  feldspar  and  mica, 
which  have  a  tendency  to  weaken  the  stone. 


x32  BUILDING  CONSTRUCTION. 

Sandstones  are  of  a  great  variety  of  colors  ;  brown,  red,  pink,  gray, 
buff,  drab  or  blue,  in  varying  shades,  being  common  varieties  ;  the 
color  being  due  largely  to  the  iron  contained  in  the  stone.  The 
oxides  of  iron  do  no  harm  in  the  stone,  but  no  light-colored  sandstone 
should  be  used  for  exterior  work  which  contains  iron  pyrites  (or  sul- 
phate of  iron),  as  the  iron  is  almost  sure  to  stain  or  rust  the  stone. 

Sandstones  vary  in  texture  from  almost  impalpable  fine-grained 
stores  to  those  in  which  the  grains  are  like  coarse  sand.  All  other 
conditions  being  the  same,  the  fine-grained  stones  will  be  the  strongest 
and  most  durable  and  take  the  sharpest  edge.  Sandstones  being  of 
a  sedimentary  formation,  they  are  often  laminated,  or  in  layers,  and 
if  the  stone  is  set  "on  edge,"  or  with  its  natural  bed  or  surface  par- 
allel to  the  face  of  the  wall,  the  surface  of  the  stone  is  quite  sure  in 
time  to  disintegrate  or  peel  off.  All  laminated  stones  should  always  be 
laid  on  their  natural  bed.  When  freshly  quarried,  sandstones  gener- 
ally contain  a  considerable  quantity  of  water,  which  makes  them  soft 
and  easy  to  work,  but  at  the  same  time  very  liable  to  injury  by  freez- 
ing if  quarried  in  winter  weather.  Many  Northern  quarries  cannot 
be  worked  in  winter  on  this  account.  Most,  if  not  all,  sandstones 
harden  as  the  quarry  water  evaporates,  so  that  many  stones  which  are 
very  soft  when  first  quarried  become  hard  and  durable  when  placed 
in  the  building.  Such  stones,  however,  should  not  be  subjected  to 
much  weight  until  they  have  dried  out. 

There  is  a  great  abundance  of  fine  sandstone  of  all  colors  distributed 
throughout  the  United  States,  so  that  it  is  not  difficult  to  get  a  first- 
class  stone  for  any  building  of  importance.  Most  of  the  sandstones 
in  the  Eastern  part  of  the  country  are  either  red  or  brown  in  color 
there  being  no  merchantable  light  sandstones  east  of  Ohio. 

159.  The  following  are  the  best  known  sandstones  in  this  country, 
any  of  which  are  good  building  stones  : 

Connecticut  brownstone  includes  all  the  dark  brown  sandstones  quarried  in  the 
neighborhood  of  Portland,  Conn.  It  is  a  handsome  dark  brown  stone,  tinted  slightly 
reddish,  has  a  fine  even  rift,  is  easy  to  work,  and  gives  a  beautiful  surface  when 
rubbed.  This  stone  is  decidedly  laminated,  and  the  surface  will  soon  peel  if  the  stone 
is  set  on  edge.  When  laid  on  its  natural  bed,  however,  it  is  very  durable.  This 
was  the  first  sandstone  quarried  in  the  country,  and  great  quantities  of  it  have  been 
used  in  New  York  City. 

Longmeadow  Stone.— This  is  a  reddish-brown  sandstone  quarried  principally  at 
East  Longmeadow,  Mass.  It  is  an  excellent  building  stone,  without  any  apparent 
bed,  and  may  be  cut  any  way.  It  varies  from  quite  soft  to  very  hard  and  strong 
stone,  and  should  be  selected  for  good  work.  It  has  been  largely  used  throughout 
the  New  England  States  for  the  past  fifteen  years. 


BUILDING  STONES.  133 

Potsdam  Red  Sandstone,  from  Potsdam,  N.  Y.,  is  a  quartzite  and  one  of  the  best 
building  stones  in  the  country,  being  extremely  durable  and  equal  to  granite  in 
strength.  It  was  used  in  the  buildings  of  Columbia  College,  New  York  City  ;  All 
Saints  Cathedral,  in  Albany,  and  in  the  Dominion  Houses  of  Parliament,  in  Ottawa, 
Canada.  There  are  three  shades,  chocolate,  brick-red  and  reddish-cream. 

Hummelstown  Brownstone,  from  Hummelstown,  Pa.,  is  a  medium  fine-grained 
stone,  bluish-brown  or  slightly  purple  in  color,  the  upper  layers  being  more  of  a  red- 
dish-brown and  much  resembling  the  Connecticut  stone.  The  stone  compares  very 
favorably  with  the  other  brownstones  mentioned,  and  is  in  very  general  use  in  the 
principal  Eastern  cities. 

North  Carolina,  West  Virginia  and  Indiana  contain  quarries  of  brownstone  which 
supply  the  local  demand  and  which  are  worthy  of  a  wider  distribution,  particularly 
that  of  North  Carolina. 

Fond  du  Lac,  Minnesota,  furnishes  a  reddish-brown  sandstone  closely  resembling 
the  Connecticut  brownstone,  but  much  harder  and  firmer.  "The  stone  consists 
almost  wholly  of  quartz  cemented  with  silica  and  iron  oxides." 

Ohio  Stone. — The  finest  quality  of  light  sandstone  in  the  United  States  is  quarried 
in  the  towns  of  Amherst,  Berea,  East  Cleveland,  Illyria  and  Independence,  Ohio, 
and  is  commonly  known  as  Ohio  stone  or  Berea  stone.  It  is  a  fine-grained,  homo- 
genous sandstone,  of  a  very  light  buff,  gray  or  blue-gray  color,  and  very  evenly 
bedded.  The  stone  is  about  95  per  cent,  silica,  the  balance  being  made  up  of  small 
amounts  of  lime,  magnesia,  iron  oxides,  alumina  and  alkalies.  There  is  but  little 
cementing  material,  the  various  particles  being  held  together  mainly  by  cohesion 
induced  by  the  pressure  to  which  they  were  subjected  at  the  time  of  their  consolida- 
tion. They  are  very  soft  and  work  readily  in  every  direction,  and  are  especially 
fitted  for  carving. 

' '  Unfortunately  the  Berea  stone  nearly  always  contains  more  or  less  iron  pyrites 
and  needs  to  be  selected  with  care.  Most  of  the  quarries,  however,  have  been  trav- 
ersed by  atmospheric  waters  to  such  a  degree  that  all  processes  of  oxidation  which 
are  possible  have  been  very  nearly  completed."  * 

The  stone  can  be  furnished  in  blocks  of  any  desired  size  and  of  uniform  color. 
The  stone  is  shipped  to  all  parts  of  the  country,  and  is  in  great  demand  for  fine 
buildings.  Mr.  H.  H.  Richardson,  the  celebrated  architect,  often  used  it  in  con- 
trast with  the  Longmeadow  sandstone  for  trimmings  and  decorative  effects.  The 
stone  contains  from  about  6  to  8  per  cent,  of  water  when  first  taken  from  the  quarry, 
and  about  4  per  cent,  when  dry.  The  stone  cannot  be  quarried  in  winter  on  account 
of  the  splitting  of  the  stone  caused  by  the  freezing  of  the  water  contained  in  it. 
There  are  some  fourteen  or  fifteen  different  companies  that  quarry  this  stone  for  the 
market. 

"  The  Waverly  sandstone  comes  from  Southern  Ohio.  This  is  a  fine-grained, 
homogenous  stone  of  a  light  drab  or  dove  color,  works  with  facility,  and  is  very 
handsome  and  durable.  It  forms  the  material  of  which  many  of  the  finest  buildings 
in  Cincinnati  are  constructed,  and  is,  justly,  highly  esteemed  there  and  elsewhere.  "\ 

Ohio  is  the  largest  producer  of  sandstone  of  any  State  in  the  Union. 

At  Warrensburg,  Mo. ,  is  quarried  a  gray  sandstone  which  has  been  used  in  many 
important  buildings  in  Kansas  City. 


*  "  Stones  for  Building  and  Decoration,"  pp.  276-277. 
•f  Baker,  "  Masonry  Construction,"  p.  30. 


i34  BUILDING  CONSTRUCTION. 

The  Rocky  Mountain  region  also  furnishes  great  quantities  of  fine  sandstones.  In 
Arizona  is  quarried  a  very  fine-grained  chocolate  sandstone,  which  takes  a  fine  edge 
and  is  excellently  adapted  for  rubbed  and  moulded  work.  A  considerable  quantity 
of  it  is  used  in  Denver,  Col.,  on  account  of  its  pleasing  color,  and  it  is  also  shipped 
east  of  the  Missouri  River. 

At  Manitou,  Col. ,  are  inexhaustible  quarries  of  a  fine  red  stone,  much  resembling 
the  L9ngmeadow  stone  of  Massachusetts,  but  of  a  lighter  red  color.  It  has  no  appar- 
ent bed  and  weathers  well.  It  has  sufficient  strength  for  ordinary  purposes.  At  Fort 
Collins,  Col.,  is  quarried  a  much  harder  and  slightly  darker  stone,  which  is  an  excel- 
lent stone  for  almost  any  purpose.  It  has  sufficient  strength  for  piers  and  columns, 
and  is  hard  enough  for  steps  and  thresholds.  It  is  much  harder  to  cut  than  the 
Manitou  stone,  and  hence  is  more  expensive,  but  it  is  more  durable.  This  stone  has 
been  shipped  as  far  East  as  New  York  City.  Colorado  also  contains  an  inexhaustible 
supply  of  sandstone  flagging,  admirably  adapted  for  foundations  and  sidewalks;  it  is 
as  strong  as  granite,  and  may  be  quarried  in  slabs  of  almost  any  size  or  thickness. 

A  red  and  buff  sandstone  is  quarried  at  Glenrock,  Wyoming,  which  has  been  used 
in  Omaha,  Nebraska. 

California  has  fifteen  quarries  of  sandstone,  the  larger  number  of  which  are  in 
Santa  Clara  County.  Stanford  University  is  built  of  a  light-colored  sandstone  quar- 
ried at  San  Jose,  Cal. 

Owing  to  the  sparsely  settled  condition  of  the  country  and  the  lack  of  railroad 
facilities,  the  building  stones  of  the  Western  portion  of  the  United  States  have  been 
but  little  developed,  but  with  the  building  up  of  the  country  the  quarrying  industry 
will  undoubtedly  become  one  of  great  importance. 

160.  Lava  Stone  or  Turfa. — Near  Castle  Rock,  in  Colorado, 
is  quarried  a  soft,  very  light  gray  and  pink  stone  of  volcanic  origin, 
which  is  commonly  called  lava  stone.  It  is  extremely  light  in  weight, 
weighing  only  about  no  pounds  per  cubic  foot,  and  can  be  cut  with 
a  knife.  It  weathers  better  than  the  soft  sandstones,  and  its  color 
makes  it  very  suitable  for  rock  face  ashlar.  It  is  difficult  to  obtciin  in 
large  blocks,  and  is  full  of  clay  or  air  holes  and  often  of  invisible 
cracks,  which  render  it  dangerous  for  use  in  heavy  buildings,  but  for 
dwellings  it  makes  a  very  cheap,  durable  and  pleasing  stone.  Owing 
to  the  small  air  holes  which  it  contains  it  does  not  receive  a  finished 
surface,  and  is  most  effective  when  used 'rock  face.  There  are  a 
great  many  houses  and  several  public  buildings  in  Denver  built  of 
this  stone.  A  similar  stone  occurs  in  the  vicinity  of  the  Las  Vegas 
Hot  Springs,  and  Albuquerque,  New  Mexico. 

Blue  Shale  is  a  variety  of  sandstone  that  is  dark  blue  in  color, 
quite  dense  and  hard,  and  makes  a  fair  material  for  foundations.  As 
a  rule  it  does  not  work  readily  and  often  contains  iron  pyrites,  which 
renders  it  unsuitable  for  ashlar  or  trimmings. 

The  only  stone  in  many  localities  is  a  hard,  igneous  rock,  called 
trap,  which  is  suitable  for  foundations,  but  cannot  be  cut  easily. 


BUILDING  STONES.  135 

Such  stones  are  only  used  for  local  purposes  when  no  other  can  be 
obtained  except  at  great  expense. 

l6l.  Slate. — Although  slate  is  not  strictly  a  building  stone,  yet  it 
is  largely  used  for  covering  the  roofs  of  buildings,  for  blackboards, 
sanitary  purposes,  etc.,  and  the  architect  should  be  familiar  with  its 
qualities  and  characteristics. 

The  ordinary  slate  used  for  roofing  and  other  purposes  is  a  com- 
pact and  more  or  less  metamorphosed  siliceous  clay.  Slate  stones 
originated  as  deposits  of  fine  silt  on  ancient  sea  bottoms,  which  in  the 
course  of  time  became  covered  with  thousands  of  feet  of  other  mate- 
rials and  finally  turned  into  stone. 

"  The  valuable  constituents  in  slate  are  the  silicates  of  iron  and 
alumina,  while  the  injurious  constituents  are  sulphur  and  the  carbon- 
ates of  lime  and  magnesia." 

One  of  the  most  valuable  characteristics  of  slate  is  its  decided  ten- 
dency to  split  into  thin  sheets,  whose  surfaces  are  so  smooth  that  they 
lie  close  together,  thus  forming  a  light  and  impervious  roof  covering. 
These  planes  of  cleverage  are  caused  6y  intense  lateral  pressure,  and 
are  generally  at  very  considerable  though  varying  angles  with  the 
ancient  bedding. 

The  most  valuable  qualities  of  slate  are  its  strength,  toughness  and 
non-absorption. 

Strength  and  Hardness. — From  various  tests  that  have  been  made 
on  the  quality  of  slate,  it  appears  that,  in  general,  the  strongest  spec- 
imens are  the  heaviest  and  softest,  as  also  the  least  porous  and  cor- 
rodible.  "  The  tests  for  strength  and  corrodibility  are  probably  those 
of  greatest  importance  in  forming  an  opinion  regarding  the  value  of 
the  slate  under  actual  conditions  of  service."  * 

Mr.  Mansfield  Merriman  suggests  that  specifications  should  require 
roofing  slates  to  have  a  modulus  of  rupture  for  transverse  strength 
greater  than  7,000  pounds  per  square  inch. 

If  the  slate  is  too  soft,  however,  the  nail  holes  will  become  enlarged 
and  the  slate  will  get  loose.  If  it  is  too  brittle  the  slate  will  fly  to 
pieces  in  the  process  of  squaring  and  holing,  and  will  be  easily  broken 
•on  the  roof.  "  A  good  slate  should  give  out  a  sharp  metallic  ring 
when  struck  with  the  knuckles  ;  should  not  splinter  under  the  slater's 
axe  ;  should  be  easily  '  holed  '  without  danger  of  fracture,  and  should 
not  be  tender  or  friable  at  the  edges." 

The  surface  when  freshly  split  should  have  a  bright  metallic  lustre 
and  be  free  from  all  loose  flakes  or  dull  surfaces. 


*  Mansfield  Merriman  in  Stone,  April,  1895. 


136  BUILDING  CONSTRUCTION. 

Color. — The  color  of  slates  varies  from  dark  blue,  bluish-black  and 
purple  to  gray  and  green.  There  are  also  a  few  quarries  of  red  slate. 
The  color  of  the  slate  does  not  appear  to  indicate  the  quality.  The 
red  and  dark  colors  are  generally  considered  the  most  effective,  and 
the  greens  are  generally  used  only  on  factories,  storehouses  and 
buildings  where  the  appearance  is  not  of  so  much  importance. 

Some  slates  are  marked  with  bands  or  patches  of  a  different  color, 
and  the  dark  purple  slates  often  have  large  spots  of  light  green  upon 
them.  These  spots  do  not  as  a  rule  affect  the  durability  of  the  slate, 
but  they  greatly  detract  from  its  appearance. 

As  a  rule  the  dark  color  of  slate,  particularly  that  of  the  slates  of 
Maine  and  Pennsylvania,  appears  to  be  due  to  particles  of  carbona- 
ceous matter  contained  in  the  slate. 

"  The  red  slates  of  New  York  are  made  up  of  a  ground  mass  of 
impalpable  red  dust  in  which  are  imbedded  innumerable  quartz  and 
feldspar  particles." 

Absorption. — A  good  slate  should  not  absorb  water  to  any  percep- 
tible extent,  and  if  a  slate  is  immersed  in  water  half  its  height  the 
water  should  not  rise  in  the  upper  half  ;  if  it  does  it  shows  that  the 
slate  is  not  of  good  quality. 

"  If,  upon  breathing  upon  a  slate,  a  clayey  odor  be  strongly  emitted, 
it  may  be  inferred  that  the  slate  will  not  weather." 

Grain. — A  good  slate  should  have  a  very  fine  grain,  and  the  slates 
should  be  cut  lengthways  of  the  grain,  so  that  if  a  slate  breaks  on  the 
roof  it  will  not  become  detached,  but  will  divide  into  two  slates,  each 
held  by  a  nail. 

Market  Qualities. — The  market  qualities  of  slate  are  classed  accord- 
ing to  their  straightness,  smoothness  of  surface,  fair,  even  thickness, 
and  according  to  the  presence  or  absence  of  discoloration. 

Uses. — The  principal  use  of  slate  is  for  roofing  purposes,  but  it  is 
also  used  for  billiard  tables,  mantels,  floor  tiles,  steps,  flagging,  fit- 
tings for  toilet  rooms,  and  for  school  blackboards. 

162.  Distribution  and  Varieties  of  Slate.— The  distribu- 
tion of  the  slate  industry  among  the  different  States  in  1890  is  best 
shown  by  the  following  figures,  which  give  the  value  of  the  product : 

Pennsylvania,  $2,011,776  ;  Vermont,  $838,013  ;  Maine,  $214,000  ; 
New  York,  $130,000;  Maryland,  $110,008;  Virginia,  $85,079; 
Georgia,  $15,330;  Michigan,  $15,000 ;  California,  $13,889;  New 
Jersey,  $10,985  ;  Arkansas,  $240. 

Slates  are  classified  in  the  trade,  however,  by  the  name  of  the 
region  in  which  they  are  quarried,  some  regions  extending  into  two 


BUILDING  STONES.  137 

or  more  States,  while  several  regions  are  contained  in  the  State  of 
Pennsylvania.  The  product  from  each  region  is  more  or  less  distinc- 
tive from  that  of  other  regions.  The  more  important  producing 
regions  are : 

Number  of 

Quarries.  Product. 

Vermont  and  New  York  region 76  $968,616 

Bangor  region,  Pennsylvania 2O  707, 162 

Lehigh  region,  Pennsylvania 45  690,432 

Pen  Argyl  region,  Pennsylvania 17  393,030 

Maine  region 4  214,000 

Northampton  hard-vein  region,  Pennsylvania 18  184,595 

Peach  Bottom  region,  Maryland  and  Pennsylvania. ...     9  146,565 

Virginia  region 3  85,079 

The  slates  of  the  Bangor,  Pen  Argyl  and  Lehigh  regions  and  the 
Northampton  hard  veined  slates  are  found  in  the  extensive  slate  for- 
mation known  as  the  Hudson  River  Division  of  the  lower  Silurian 
deposits,  while  the  slate  formations  of  Vermont  and  New  York, 
Maine  and  the  Peach  Bottom  region,  probably  belong  to  the  Cam- 
brian Division,  whose  place  in  the  geological  series  is  lower  and  older 
than  the  Silurian  rocks. 

"  The  slates  of  the  Cambrian  formation  are  usually  regarded  as 
better  in  respect  to  strength  and  weathering  qualities  than  those  of 
the  Silurian  age,  the  market  price  of  some  varieties  of  the  former 
being,  indeed,  more  than  double  that  of  the  common  kinds  of  the 
latter." 

Vermont  and  New  York  Region. — In  the  western  portion  of  Vermont  are 
extensive  quarries  of  slate,  the  product  being  used  for  all  the  different  purposes  for 
which  the  material  is  adapted. 

The  stone  is  soft  and  uniform  in  texture,  and  can  be  readily  planed  or  sawed  with 
a  circular  steel  saw  like  wood. 

The  slates  from  this  region  vary  greatly  in  color,  and  are  classified  and  sold  under 
the  following  names: 

Sea-green,  unfading  green,  uniform  green,  bright  green,  red,  bright  red,  purple, 
variegated  and  mottled. 

The  true  sea-green  slate  is  found  only  in  this  State,  but  it  fades  and  changes  color 
badly. 

Red  Slate. — Nearly  all  the  red  slate  used  in  the  United  States  is  quarried  in  the 
neighborhood  of  Granville,  near  the  Vermont  line,  in  New  York  State.  "The  slates 
of  this  formation  are  of  a  brick-red  and  green  color,  both  varieties  often  occurring  in 
the  same  quarry."  The  slate  is  of  good  quality  and  is  almost  entirely  used  for  roof- 
ing purposes,  its  color  making  it  especially  desirable  for  fine  residences  and  public 
buildings.  Owing  to  the  limited  quantity,  this  slate  brings  about  three  times  the 
price  of  the  dark  slates. 

Maine  Region. — The  quarries  in  this  region  are  located  at  Monson,  Blanchard 
and  Brownville,  Piscataquis  County.  The  stone  is  of  a  blue-black  color,  of  excel- 


138  BUILDING  CONSTRUCTION. 

lent  quality,  being  hard,  yet  splitting  readily  into  thin  sheets  with  a  fine  surface. 
They  are  not  subject  to  discoloration,  and  give  forth  a  clear  ringing  sound  when 
struck.  The  Brownville  slate  is  said  to  be  the  toughest  slate  in  the  world.  Slate 
from  this  quarry,  after  fifty  years'  exposure,  looks  as  bright  and  clean  as  when  new. 
The  Maine  quarries  furnish  nearly  all  the  black  slates  used  in  New  England. 
The  product  is  also  extensively  used  for  slates,  blackboards  and  sanitary  purposes. 

I63.- 

Pennsylvania  Slates. — Bangor  Region. — This  region  is  entirely  within  North- 
ampton County,  and  is  the  most  important,  in  point  of  production,  in  the  country. 
The  principal  quarries  are  at  Bangor,  East  Bangor  and  Slatington.  The  color  is 
a  uniform  dark  blue  or  blue-black.  This  slate  is  used  very  extensively  for  black- 
boards and  school  slates,  as  well  as  for  roofing  purposes.  Average  modulus  of  rup- 
ture, 9,810  pounds. 

The  Lehigh  region  includes  Lehigh  County  entire  and  a  few  quarries  in  Berk  and 
Carbon  Counties  and  opposite  Slatington  in  Northampton  County.  The  product  is 
similar  to  that  of  the  Bangor  region. 

Pen  A  rgyl  region  embraces  quarries  at  Pen  Argyl  and  Wind  Gap  in  Northamp- 
ton County. 

The  Northampton  hard-vein  region  includes  the  Chapman,  Belfast  and  other 
quarries,  all  in  Northampton  County.  This  region  is  distinguished  on  account  of 
the  extreme  hardness  of  the  slate  as  compared  with  that  produced  in  other  regions  of 
the  State.  The  product  is  considered  as  the  best  of  the  Silurian  slates,  its  extreme 
hardness  being  generally  considered  as  an  advantage  to  the  slate,  rendering  it  dur- 
able and  non-absorptive.  It  is  especially  suitable  for  flagging.  Average  modulus 
of  rupture,  about  8,480  pounds. 

Peach  Bottom  Region. — The  celebrated  "Peach  Bottom  Slate"  is  taken  from  a 
narrow  belt  scarcely  6  miles  long  and  a  mile  wide,  extending  across  the  southeastern 
portion  of  York  County  and  into  Hartford  County,  in  Maryland.  The  stone  is 
tough,  fine  and  moderately  smooth  in  texture,  blue-black  in  color,  and  does  not  fade 
on  exposure,  as  has  been  proven  by  seventy  five  years'  wear  on  the  roofs  of  build- 
ings. It  also  ranks  very  high  for  strength  and  durability,  and  is  generally  consid- 
ered equal,  if  not  superior,  to  any  slate  in  the  country.  The  average  modulus  of 
rupture  of  twelve  specimens  was  1 1 . 260  pounds,  the  lowest  value  being  8, 320  pounds. 

The  northern  peninsula  of  Michigan  contains  an  inexhaustible  supply  of  good 
roofing  slate,  and  extensive  quarries  have  been  opened  about  15  miles  from  L'Anse 
and  about  3  miles  from  Huron  Bay.  "The  stone  here  is  susceptible  of  being  split 
into  large,  even  slabs  of  any  desired  thickness,  with  a  fine,  silky,  homogenous 
grain,  and  combines  durability  and  toughness  with  smoothness.  Its  color  is  an 
agreeable  black  and  very  uniform."* 

A  goc  d  blue-black  roofing  slate  is  quarried  in  Bingham  County,  Virginia,  which 
bids  fair  to  supplant  other  slates  in  that  section  of  the  country. 

Quarries  in  Polk  County,  Georgia,  furnish  most  of  the  roofing  slates  for  Atlanta 
and  neighboring  towns. 

Good  roofing  slate  is  also  known  to  occur  in  California,  Colorado  and  Dakota, 
but  the  first  State  mentioned  is  the  only  one  in  which  quarries  have  yet  been  opened. 

*  "  Stones  for  Building  and  Decoration,"  p.  302. 


BUILDING  STONES.  139 

164.  Soapstone. — Although  not  properly  a  building  stone,  soap- 
stone  is  used  more  or  less  in  the  fittings  of  buildings,  especially  for 
sinks  and  wash  trays,  and  for  the  linings  of  fireplaces. 

Soapstone  is  a  dark  bluish-gray  rock,  composed  essentially  of  the 
mineral  talc. 

The  stone  is  soft  enough  to  be  cut  readily  with  a  knife,  or  even 
with  the  thumb  nail,  and  has  a  decided  soapy  feeling,  hence  its  name. 

Although  so  soft,  this  stone  ranks  amongst  the  most  indestructible 
and  lasting  of  rocks.  At  present  its  chief  use  is  in  the  form  of  slabs 
about  i^  inches  thick,  for  stationary  washtubs  and  sinks,  for  which  it 
is  one  of  the  best  materials.  Soapstone  also  offers  great  resistance  to 
heat,  and  is  often  used  for  lining  fireplaces. 

At  one  time  it  was  extensively  used  in  New  England  in  the  manu- 
facture of  heating  stones.  Considerable  quantities  of  powdered  soap- 
stone  are  used  for  making  slate  pencils  and  crayons,  as  a  lubricant  for 
certain  kinds  of  machinery,  and  in  the  finishing  coat  on  plastered 
walls. 

The  principal  quarries  producing  block  stone  are  situated  in  the 
States  of  New  Hampshire,  Vermont  and  Pennsylvania. 

The  State  of  North  Carolina  produces  most  of  the  powdered  soap- 
stone,  which  is  quarried  in  small  pieces  and  ground  in  a  mill. 

SELECTION  OF  BUILDING  STONES. 

165.  The  selection  of  a  stone  for  structural  purposes  is  a  matter  of 
the  greatest  importance,  especially  when  it  is  to  be  used  in  the  con- 
struction of  large  and  expensive  buildings.     The  cities  of  Northern 
Europe  are  full  of  failures  in  the  stones  of  important  structures,  and 
even  in  the  cities  of  the  Northern  portion  of  the  United  States  the 
examples  of  stone  buildings  which  are  falling  into  decay  are  only  too 
numerous. 

"  The  most  costly  building  erected  in  modern  times — the  Parlia- 
ment House  in  London — was  built  of  a  stone  taken  on  the  recom- 
mendation of  a  committee  representing  the  best  scientific  and  tech- 
nical skill  of  Great  Britain.  The  stone  selected  was  submitted  to 
various  tests,  but  the  corroding  influences  of  a  London  atmosphere 
were  overlooked.  The  great  structure  was  built  (of  magnesian  lime- 
stone), and  now  it  seems  questionable  whether  it  can  be  made  to 
endure  as  long  as  a  timber  building  would  stand,  so  great  is  the  effect 
of  the  gases  of  the  atmosphere  upon  the  stone."  * 

*  Baker  in  "  Masonry  Construction,"  p.  4. 


1 40  BUILDING  CONSTRUCTION. 

Stone  should  be  studied  with  reference  to  its  hardness,  durability, 
beauty,  chemical  composition,  structure  and  resistance  to  crushing. 

166.  Climate.— In  selecting  a  building  stone  the  climate,  together 
with  the  location,  with  especial  reference  to  the  proximity  to  large 
cities  and  manufacturing  establishments,  should  be  first  considered. 
There  is  many  a  porous  sand  or  limestone  which  could  endure  an  expos- 
ure of  hundreds  of  years  in  a  climate  like  that  of  Florida,  New  Mexico, 
Colorado  or  Arizona,  which  would  be  sadly  disintegrated  at  the  end  of 
a  single  season  in  one  of  the  Northern  States.     The  climate  of  our 
Northern  and  Eastern  States,  with  an  annual  precipitation  of  some  39 
or  40  inches  and  a  variation  in  temperature  sometimes  reaching  120°, 
is  very  trying  on  stonework,  and  unless  a  stone  is  suited  to  the  condi- 
tions in  which   it  is  placed,  there  are  few  materials  more  liable  to 
decay  and  utter  failure. 

167.  Color. — The   great   governing   point  with   an   architect  in 
selecting  a  building  stone  is  generally  the  color.     This  again  is  lim- 
ited to  a  choice  between  those  stones  which  come  within  the  limit  of 
cost,  and  should  be  finally  overruled  by  the  question  of  durability. 
The  architect  is  too  apt  to  think  that  if  a  building  cannot  be  pleasing 
both  in  form  and  color  it  had  better  not  be  built  at  all,  but  he  should 
keep  in  mind  not  only  how  the  building  will  look  when  just  com- 
pleted, but  how  it  will  appear  at  the  end  of  a  few  years,  and,  again, 
at  the  end  of  half  a  century.     It  is  better  that  the  colors  be  a  little 
harsh  and  inharmonious  at  first,  if  durability  is  gained  thereby,  than 
to  use  the  most  pleasing  color  only  to  see  it  entirely  changed  at  the 
end  of  a  year,  and  crumbling  in  pieces  at  the  end  of  a  decade. 

A  durable  stone  of  any  color  generally  tones  down  and  becomes 
more  pleasing  at  the  end  of  a  few  years,  while  one  that  is  not  durable 
and  permanent  in  color  very  soon  becomes  an  eyesore. 

In  the  country  and  small  towns  where  there  is  no  manufacturing, 
and  where  little  bituminous  coal  is  used,  light-colored  stones  may  be 
used  with,  the  prospect  of  their  color  remaining  unchanged  ;  but  in 
large  cities  and  in  manufacturing  towns,  particularly  those  where 
bituminous  coal  is  the  principal  fuel,  light  stones  should  be  avoided, 
and  for  such  localities  a  red  or  brown  siliceous  sandstone  is  the  most 
enduring  and  permanent,  and  next  to  this  comes  granite. 

In  a  city  like  Chicago,  the  darker  the  stone  used  the  more  perma- 
nent will  be  its  color  (that  is,  in  the  central  portion  of  the  city),  as 
both  brick  and  stone  assume  a  dirty,  dark  bronze  color  in  a  few- 
years,  and  in  such  localities  delicate  colors  and  fine  carving  are  out 
of  place. 


BUILDING  STONES.  141 

In  climates  like  that  of  Colorado,  Arizona  and  New  Mexico,  where 
there  is  a  very  bright  sun  and  almost  no  rain,  the  light  stones,  and 
particularly  marbles,  are  most  effective,  as  the  shadows  on  such  stones 
are  very  marked,  and  all  kinds  of  ornament  are  made  much  more 
prominent  than  on  red  or  dark '  stones,  and  any  compact  stone  will 
last  for  centuries  above  the  ground. 

As  a  rule,  all  else  being  equal,  the  stone  which  holds  its  native 
color  best  will  be  most  beautiful  in  a  building,  and  of  the  stones 
which  change  color,  that  will  be  most  desirable  which  changes  least 
and  evenly. 

168.  Durability. — Naturally  the  durability  of  a  stone  is  of  the 
first  importance,  for  unless  the  stone  will  last  a  reasonable  length  of 
time,  the  money  spent  on  the  structure  will  be  largely  wasted,  and 
all  public  buildings  should  be  built  of  material  that  is  practically 
imperishable. 

The  following  table,  taken  from  the  Report  of  the  Tenth  Census, 
1880,  Vol.  X.,  p.  391,  gives  the  number  of  years  that  different  stones 
have  been  found  to  last  in  New  York  City,  without  discoloration  or 
disintegration  to  the  extent  of  necessitating  repairs  : 

Coarse  brownstone 5  to    15 

Fine  laminated  brownstone 20  to    50 

Compact  brownstone 100  to  200 • 

Bluestone  (sandstone),  untried Probably  centuries 

Nova  Scotia  sandstone,  untried Perhaps  50  to  200 

Ohio  sandstone  (best  siliceous  variety), 

Perhaps  from  one  to  many  centuries 

Coarse  fossiliferous  limestone 20  to    40 

Fine  oolitic  (French)  limestone 30  to    40 

Marble,  coarse  dolomite 40 

Marble,  fine  dolomite 60  to    80 

Marble,  fine , 50  to  100 

Granite 75  to  200 

Gneiss 50  years  to  many  centuries 

There  are  many  circumstances  and  conditions,  aside  from  the  qual- 
ity of  the  stone,  that  affect  the  durability  of  exposed  stonework,  the 
more  important  of  which  are  heat  and  cold,  composition  of  the 
atmosphere,  position  of  the  stone  in  the  building,  and  manner  of 
dressing  the  stone. 

169.  Heat  and  Cold. — The  most  trying  conditions  to  which  a. 
building  stone  is  subject  are  the   ordinary  changes  of  temperature 
which  prevail  in  the  Northern  and   Eastern   States.     "  Stones,  as  a; 
rule,  possess  but  a  low  conducting  power  and  slight  elasticity.     They- 


1 42  BUILDING  CONSTRUCTION. 

are  aggregates  of  minerals,  more  or  less  closely  cohering,  each  of 
which  possesses  degrees  of  expansion  and  contraction  of  its  own.  As 
temperatures  rise  each  and  every  constituent  expands  more  or  less, 
crowding  with  resistless  force  against  its  neighbor  ;  as  the  tempera- 
tures decrease  a  corresponding  contraction  takes  place.  Since  the 
temperatures  are  ever  changing,  often  to  a  considerable  degree,  so, 
within  the  mass  of  the  stone,  there  is  continual  movement  among  its 
particles.  Slight  as  these  movements  may  be  they  can  but  be  con- 
ducive of  one  result,  a  slow  and  gradual  weakening  and  disintegra- 
tion." *  This  is  supposed  to  be  the  chief  cause  of  the  disintegration 
of  granites. 

There  are  several  examples  of  old  stonework  in  New  York  City 
that  have  begun  to  decay  on  the  south  and  west  sides,  where  the  sun 
shines  the  longest,  but  not  on  the  north  and  east.  The  effects  of 
moderate  temperatures  upon  stones  of  ordinary  dryness  are,  however, 
slight  when  compared  with  the  effects  of  freezing  upon  stones  satu- 
rated with  moisture.  The  pressure  exerted  by  water  passing  from  a 
liquid  to  a  solid  state  amounts  to  not  less  than  138  tons  to  the  square 
foot ;  and  it  is,  therefore,  evident  that  any  porous  stone  exposed  to 
heavy  rains  and  a  temperature  several  degrees  below  the  freezing 
point  must  be  seriously  damaged  by  a  single  season's  exposure.  It  is 
also  evident  that  the  more  porous  a  stone  the  greater  will  be  the 
deterioration,  and  as  sandstones  are  the  most  porous  of  all  building 
stones  they  suffer  the  most  from  this  cause  and  granites  the  least, 
hence  granite  is  the  best  stone  for  a  base  course  or  underpinning. 
[For  the  effect  of  absorption  on  the  durability  of  stones  see  Sec- 
tion 177.] 

170.  Stone  Set  on  Bed. — When  a  stone  is  built  into  the  walls 
of  a  building  in  such  a  way  that  the  natural  layers  of  the  stone  are 
vertical,  or  on  edge,  the  water  penetrating  the  stone  and  freezing 
causes  the  surface  of  the  stone  to  exfoliate  or  peel  off  much  quicker 
and  to  a  greater  extent  than  it  would  if  the  stone  had  been  laid  with 
its  natural  bed  horizontal. 

Stones  that  are  so  situated  in  a  building  that  the  rain  will  strike 
and  wash  over  them,  such  as  sills,  belt  courses,  etc.,  also  decay  sooner 
than  the  ashlar  forming  the  face  of  the  wall,  and  should  be  of  the 
most  durable  material. 

171.  Atmospheric  Action. — The  chemical  action  of  the  gases 
of  the  atmosphere,  when  brought  by  rain  in  contact  with  the  surface 

*  "  Stones  for  Building  and  Decoration,"  p.  353. 


BUILDING  STONES.  143 

of  certain  stones,  seriously  affects  their  durability.  The  most  impor- 
tant changes  produced  by  these  agencies  are  oxidation  and  solution. 

Oxidation. — The  process  of  oxidation  is,  as  a  rule,  confined  to  those 
stones  which  contain  some  form  of  iron,  and  particularly  that  known 
as  pyrite.  If  the  iron  exists  in  the  latter  shape  it  generally  combines 
with  the  oxygen  of  the  air,  forming  the  various  oxides  and  carbonates 
of  iron,  such  as  are  popularly  known  as  "rust." 

"  If  the  sulphide  occurs  scattered  in  small  particles  throughout  a 
sandstone  the  oxide  is  disseminated  more  evenly  through  the  mass  of 
the  rock,  and  aside  from  a  slight  yellowing  or  mellowing  of  the  color, 
as  in  certain  Ohio  sandstones,  it  does  no  harm.  Indeed,  it  may  result 
in  positive  good,  by  supplying  a  cement  to  the  individual  grains  and 
thus  increasing  the  tenacity  of  the  stone."* 

If  the  pyrite  exists  in  pieces  of  any  size,  however,  it  is  almost  sure 
to  oxidize  and  stain  the  stone  so  as  to  ruin  its  appearance,  especially 
if  it  is  of  a  light  color. 

In  all  other  than  sandstones  the  presence  of  any  pyrite  is  a  very 
serious  defect,  as  it  is  almost  sure  to  rust  the  stone  and  may  also  ren- 
der it  porous  and  more  liable  to  the  destructive  effects  of  frost. 

Solution. — The  worst  effect  of  the  action  of  the  gases  of  the  atmos- 
phere in  connection  with  rain  is  in  dissolving  certain  constituents  of 
stones,  thereby  causing  their  decomposition.  Pure  water  alone  is 
practically  without  effect  on  all  stones  used  for  building,  but  in  large 
cities,  and  particularly  those  in  which  a  great  deal  of  coal  is  con- 
sumed, the  rain  absorbs  appreciable  quantities  of  sulphuric,  carbonic 
and  other  acids  from  the  air  and  conveys  them  into  the  pores  of  the 
stone,  where  they  very  soon  destroy  those  stones  whose  constituents 
are  liable  to  be  decomposed  by  such  acids. 

Carbonate  of  lime  and  carbonate  of  magnesia,  the  principal  con- 
stituents of  ordinary  marbles,  limestones  and  dolomites,  are  particu- 
larly susceptible  to  the  solvent  action  of  these  acids,  even  when  they 
are  present  only  in  very  minute  quantities,  and  on  this  account  these 
stones  are  extremely  perishable  in  large  cities  and  manufacturing 
towns.  Of  course  in  dry  climates  the  acids  are  not  conveyed  into  the 
stone  to  any  great  extent,  and  the  stones  last  much  longer  than  in  a 
damp  climate.  The  less  absorbent  a  stone  is  the  less  will  be  the  sol- 
vent action  of  the  acids,  and  the  longer  the  stone  will  last.  Dolo- 
mites are  in  this  respect  more  durable  than  limestones. 

Sandstones,  whose  cementing  material  is  composed  largely  of  iron 
or  lime,  are  also  subject  to  rapid  decay  through  the  solvent  action  of 

*  "  Stones  for  Building  and  Decoration,"  p.  360. 


i44  BUILDING  CONSTRUCTION. 

the  acidulated  rains.     The  feldspars  of  granites  and  other  rocks  are 
also  susceptible  to  the  same  influence,  though  in  a  less  degree. 

172.  Method  of  Finishing. — This  also  has  a  great  deal  to  do 
with  the  durability  of  a  stone.     As  a  rule,  the  less  jar  from  heavy 
pounding  that  the  surface  is  subjected  to,  the  more  durable  will  be 
the  surface,  for  the  reason  that  the  constant  impact  of  the  blows  tends 
to  destroy  the  adhesive  or  cohesive  power  of  the  grains,  and  thus  ren- 
ders the  stone  more '  susceptible  to  atmospheric  influences.     This 
applies  particularly  to  granites  and  limestones.     Only  granites  and 
the  hardest  sandstones  should  be  pene  or  bush  hammered  ;  all  others, 
if  dressed,  should  be  cut  with  a  chisel.     Sandstones  may  afterward 
be  finished  with  a  crandal,  if  desired.     For  granites  a  rock-face  sur- 
face would  probably  prove  most  durable,  since  the  crystalline  facets 
thus  exposed  are  best  fitted  to  shed  moisture  and  the  natural  adhesion 
of  the  grains  has  not  been  disturbed.     For  all  other  stones,  however, 
a  smoothly  sawn,  rubbed  or  polished  surface  seems  best  adapted  to  a 
variable  climate. 

173.  Strength. — Whenever  a  stone  is  to  be  used  for  foundations, 
piers,  lintels,  bearing  stones,  etc.,  its  strength  should  be  considered, 
and  if  it  has  not  been  demonstrated  by  practical  use  under  similar 
circumstances,  cubes  of  the  stone  about  6  inches  on  a  side  should  be 
carefully  tested  for  the  crushing  strength.     If  the  stone  has  all  the 
appearance  of  a  first-class  stone  of  its  kind,  its  strength  may  be 
assumed  to  be  equal  to  the  average  strength  of  stones  of  that  kind. 
The  safe  working  strength  for  piers,  etc.,  should  not  exceed  one-tenth 
of  the  crushing  strength.     Tables  giving  the  crushing  strength  of 
many  well-known   stones  and  the  safe  working  strength  for  stone 
masonry  are  given  in  the  appendix. 

The  method  in  which  a  stone  is  quarried  sometimes  has  much  to 
do  with  its  strength.  If  the  stone  is  quarried  by  means  of  explosives 
the  stone  may  contain  minute  cracks,  which  cannot  be  discovered 
until  the  stone  receives  its  load,  when  their  presence  is  unpleasantly 
manifested.  Such  an  occurrence  could  only  take  place  in  some  stone 
like  lava  or  conglomerates.  The  cracking  and  splitting  of  stones  in 
buildings  is  often  due  more  to  imperfect  setting  than  to  lack  of 
strength  in  the  stone.  Any  stone  that  will  meet  the  requirements  for 
durability  will  have  sufficient  strength  for  all  purposes,  except  in  the 
positions  mentioned  above. 

Hardness. — For  many  purposes  the  hardness  of  a  stone  must  be 
considered,  as  when  it  is  to  be  used  for  steps,  door  sills,  paving,  etc. 


BUILDING  STONES.  145 

Granite,  quartzite,  or  siliceous  sandstone,  and   bluestone  are  the  best 
stones  for  this  purpose. 

Cheapness. — This  often  has  more  to  do  with  the  choice  of  a 
building  stone  by  the  owner  than  the  architect  could  wish.  The  cost 
of  the  stone  when  cut  depends  not  only  upon  the  cost  of  the  rough 
stone  delivered  at  the  site,  but  also  upon  the  ease  with  which  the 
stone  may  be  worked  ;  whether  the  stone  is  to  be  smooth  or  rock 
face  ;  plain  or  moulded  ;  and  also  to  some  extent  upon  its  weight. 
One  stone  may  be  cheaper  than  another  in  the  rough,  but  the  extra 
labor  of  cutting  may  make  it  the  most  expensive  when  put  in  the 
wall.  The  heavier  a  stone  is  the  greater  will  be  the  cost  of  setting 
and  transportation. 

174.  Fire  Resistance. — The  ability  of  a  stone  to  withstand  the 
action  of  fire  is  often  of  much  consequence,  especially  when  it  is 
exposed  to  fire  risks  on  all  sides,  as  is  the  case  with  most  business 
blocks.     Of  the  different  kinds  of  stone  used  for  building  the  com- 
pact, fine-grain  sandstones  withstand  the  action  of  fire  the  best ; 
limestones  and  marbles  suffer  the  worst  (becoming  calcined  under  an 
intense  heat)  and  granites  are  intermediate.     The  best  sandstones 
generally  come  out  uninjured,  except  for  the  discoloration  caused  by 
smoke.     Granites  do  not  collapse,  but  the  face  of  the  stone  generally 
splits  off  and  flies  to  pieces,  often  with  explosive  violence. 

175.  New  Stones.— If ,  in  selecting  a  building  stone,  it  is  deemed 
advisable  to  use  a  stone  from  a  new  quarry,  and  the  weathering  qual- 
ities of  the  stone  have  not  been  tested  by  actual  use  in  buildings,  the 
architect  should  insist  upon  a  chemical  and  microscopic  test  of  the 
stone  by  an  expert  to  see  if  there  is  anything  in  the  composition  or 
structure  of  the  stone  that  would  render  it  unsuited  for  building  pur- 
poses, and  if  the  report  is  favorable,  and  the  stone  meets  the  tests 
described  in  the  following  sections,  he  may  then  use  it  with  a  free 
conscience. 

An  architect  cannot  be  too  careful  about  using  a  new  stone,  or  one 
that  has  not  been  used  under  similar  circumstances,  and  whenever  he 
is  obliged  to  use  such  a  stone  he  should  take  pains  to  obtain  as  much 
information  in  regard  to  it,  from  all  practical  sources,  as  possible. 

The  writer  has  known  of  a  case  in  which  a  stone,  which  had  for  a 
long  time  been  used  for  making  ashlar,  was  used  in  the  piers  under  a 
seven-story  building,  and  the  piers  commenced  to  crack  under  only 
about  one-one-hundredth  part  of  the  breaking  strength  of  the  stone 
as  given  in  a  published  report  of  tests  on  the  strength  of  stone,  and 
it  cost  nearly  $200,000  to  repair  the  damage  and  substitute  other 


146  BUILDING  CONSTRUCTION. 

stone.  The  failure  of  the  stone  (which  was  a  lava  stone)  was  sup- 
posed to  be  due  to  fine  cracks  produced  in  blasting  out  the  stone 
from  the  quarry. 

It  will  not  always  do,  either,  to  rely  upon  the  past  reputation  of  a 
stone  for  durability,  as  the  quality  of  building  stones  from  the  same 
quarry  often  differ. 

TESTING  OF  BUILDING  STONES. 

176.  Every  stone  intended  for  building  purposes  that  does  not 
come  from  some  well-known  quarry  should  be  tested  by  chemical 
analysis,  and  the  results  compared  with  the  analyses  of  well-known 
stones  of  the  same  kind,  and  if  found  to  differ  materially  in  constit- 
uents soluble  in  water  or  attached  by  sulphuric  or  carbonic  acids, 
they  should  be  rejected  ;  the  presence  of  iron  pyrites  should  also  lead 
to  the  rejection  of  the  stone,  if  intended  for  external  use.  If  the 
building  is  one  of  importance  the  architect  should  insist  on  the  own- 
ers getting  the  opinion  of  some  expert  chemist  or  mineralogist  on  the 
durability  and  weathering  qualities  of  the  stone. 

As  a  rule,  however,  most  buildings  are  now  built  from  stone  taken 
from  well-known  quarries,  whose  weathering  qualities  have  been 
proved,  so  that  if  the  quality  is  equal  to  the  best  that  the  quarry  will 
supply  the  stone  will  prove  all  that  was  expected  of  it.  The  fact, 
however,  that  certain  quarries  have  furnished  good  material  in  the 
past  is  no  guarantee  of  the  future  output  of  the  entire  quarry.  This 
is  especially  true  regarding  rocks  of  sedimentary  origin,  as  the  sand 
and  limestones,  different  beds  of  which  will  often  vary  widely  in  color, 
texture,  composition  and  durability,  though  lying  closely  adjacent. 
In  many  quarries  of  calcareous  rocks  in  Ohio,  Iowa  and  neighboring 
States,  the  product  is  found  to  vary  at  different  depths,  all  the  way 
from  a  pure  limestone  to  magnesian  limestones  and  dolomite,  and  in 
many  cases  an  equal  variation  exists  in  point  of  durability.* 

The  architect  should,  therefore,  make  a  careful  examination  of  the 
stone  as  it  is  delivered  on  the  ground,  or  in  the  yard  before  it  is  cut, 
to  see  that  the  quality  of  the  stone  is  up  to  the  standard,  and  in  large 
buildings  in  which  a  great  quantity  of  stone  will  be  required,  it  will 
be  advisable  to  visit  the  quarry  and  determine  from  which  part  of 
the  quarry  the  stone  shall  be  taken. 

The  following  rules  and  tests  will  enable  one  to  judge  if  the  stone 
is  of  a  good  quality  and  likely  to  prove  durable : 
1  % 

*"  Stones  for  Building  and  Decoration,"  p.  380. 


BUILDING  STONES.  147 

Compactness. — As  a  general  rule,  in  comparing  stones  of  the  same 
class,  the  least  porous,  most  dense  and  strongest  will  be  the  most 
durable  in  atmospheres  which  have  no  special  tendency  to  attack  the 
constituents  of  the  stone.  A  good  building  stone  should  also  give 
out  a  clear,  ringing  sound  when  struck  with  a  hammer. 

Fracture. — A  fresh  fracture,  when  examined  through  a  powerful 
magnifying  glass,  should  be  bright,  clean  and.  sharp,  with  the  grains 
well  cemented  together.  A  dull,  earthy  appearance  indicates  a  stone 
likely  to  decay. 

177.  Absorption. — One  of  the  most  important  tests  for  the  durabil- 
ity of  stone  is  that  of  the  porosity,  or  degree  with  which  the  stone 
absorbs  moisture,  since,  other  things  being  equal,  the  less  moisture  a 
stone  absorbs  the  more  durable  it  will  be. 

To  determine  the  absorptive  power  the  specimen  should  be  thor- 
oughly dried  at  about  100°  F.  and  carefully  weighed  ;  it  must  then 
be  soaked  for  at  least  twenty-four  hours  in  pure  water  ;  when  removed 
from  the  water,  the  surface  allowed  to  dry  in  the  air  and  then 
weighed.  The  increase  in  weight  will  be  the  amount  of  water 
absorbed,  and  will  stand,  although  not  absolutely  correct,  as  an 
expression  of  the  stone's  absorptive  power.  This  test  is  extremely 
simple,  and  when  done  with  care  should  give  very  practical  results. 

Any  stone  which  will  absorb  10  per  cent,  of  its  weight  of  water 
during  twenty-four  hours  should  be  looked  upon  with  suspicion  until, 
by  actual  experiment,  it  has  shown  itself  capable  of  withstanding, 
without  harm,  the  different  effects  of  the  weather  for  several  years. 
Half  of  this  amount  may  be  considered  as  too  large  when  the  stone 
contains  any  appreciable  amount  of  lime  or  clayey  matter.* 

The  porosity  of  a  stone  also  has  influence  upon  its  appearance 
when  in  the  building. 

A  non-absorbent  stone  is  washed  clean  by  each  heavy  rain,  and  its' 
original  beauty  is  retained,  while  a  porous  stone  soon  fills  with  dirt 
and  smoke  and  looks  little  better  than  a  wall  plastered  with  cement. 
Even  in  stones  for  interior  decoration  absorption  should  not  be  over- 
looked, as  ink,  oils  or  drugs  may  ruin  expensive  furnishings  if  the 
stone  is  porous. 

178.  Acid  Test.\ — Simply  soaking  a  stone  for  some  days  in  dilute 
solutions  containing  i  per  cent,  of  sulphuric  acid  and  of  hydrochloric 
acid  will  afford  a  rough  idea  as  to  whether  it  will  stand  a  town  atmos- 
phere.    A  drop  or  two  of  acid  on  the  surface  of  the  stone  will  create 


*"  Stones  for  Building  and  Decoration,"   p.  371. 
•»•"  Notes  on  Building  Construction,"  Part  III.,  p. 


M8  BUILDING  CONSTRUCTION 

an  intense  effervescence  if  there  is  a  large  proportion  present  of  car- 
bonate of  lime  or  carbonate  of  magnesia. 

Test  for  Solution. — The  following  simple  test  is  useful  for  deter- 
mining whether  a  stone  contains  much  earthy  or  mineral  matter  easy 
of  solution  : 

Pulverize  a  small  piece  of  the  stone  with  a  hammer,  put  the  pul- 
verized stone  into  a  glass  about  one-third  full  of  clear  water,  and  let 
the  particles  remain  undisturbed  at  least  half  an  hour.  Then  agitate 
the  water  and  broken  stone  by  giving  the  glass  a  circular  motion  with 
the  hand.  If  the  stone  be  highly  crystalline,  and  the  particles  well 
cemented  together,  the  water  will  remain  clear  and  transparent,  but 
if  the  specimen  contains  uncrystallized  earthy  powder,  the  water  will 
present  a  turbid  or  milky  appearance  in  proportion  to  the  quantity  of 
loose  matter  contained  in  the  stone. 

SEASONING  OF  STONE. 

179.  All  stone  is  better  for  being   exposed   in    the   air   until   it 
becomes  dry  before  it  is  set.     This  gives  a  chance  for  the  quarry 
water  to  evaporate,  and  in  nearly  all  cases  renders  the  stone  harder, 
and  prevents  the  stone  from  splitting  from  the  action  of  the  frost. 

Many  stones,  particularly  certain  varieties  of  sandstone  and  lime- 
stone, that  are  quite  soft  and  weak  when  first  quarried  acquire  con- 
siderable hardness  and  strength  after  they  have  been  exposed  to  the 
air  for  several  months.  This  hardness  is  supposed  to  be  caused  by 
the  fact  that  the  quarry  water  contained  in  the  stone  holds  in  solu- 
tion a  certain  amount  of  cementing  material,  which,  as  the  water 
evaporates,  is  deposited  between  the  particles  of  sand,  binding  them 
more  firmly  together  and  forming  a  hard  outer  crust  to  the  stone, 
although  the  inside  remains  soft,  as  at  first.  On  this  account  the 
stone  should  be  cut  soon  after  it  is  taken  from  the  quarry,  and  if  any 
carving  is  to  be  done  it  should  be  done  before  the  stone  becomes  dry, 
otherwise  the  hard  crust  will  be  broken  off  and  the  carving  will  be 
from  the  soft  interior,  and  hence  its  durability  much  lessened. 

PROTECTION  AND    PRESERVATION  OF  STONEWORK. 

180.  There  are  a  great  many  preparations  that  have  been  used  for 
preventing  the  decay  of  building  stones,  but  all  are  expensive,  and 
none  have  proved  very  satisfactory. 

Paint. — The  substance  most  generally  used  for  preserving  stone- 
work is  lead  and  oil  paint.  This  is  effectual  for  a  time,  but  the  paint 
is  destroyed  by  the  atmospheric  influences,  and  must  be  renewed 


BUILDING  STONES.  149 

every  three  or  four  years.  The  paint  also  spoils  the  beauty  of  the 
stone. 

The  White  House  at  Washington  is  built  of  a  porous  red  sand- 
stone, which  has  been  painted  white  for  many  years. 

Oil. — Boiled  linseed  oil  is  sometimes  used  on  stonework,  but  it 
always  discolors  a  light-colored  stone,  and  renders  a  dark-colored  one 
still  darker.  "  The  oil  is  applied  as  follows  :  The  surface  of  the 
stone  is  washed  clean,  and,  after  drying,  is  painted  with  one  or  more 
coats  of  boiled  linseed  oil,  and  finally  with  a  weak  solution  of 
ammonia  in  warm  water.  This  renders  the  tint  more  uniform.  This 
method  has  been  tried  on  several  houses  in  New  York  City,  and  the 
waterproof  coating  thus  produced  found  to  last  some  four  or  five 
years,  when  it  must  be  renewed.  The  preparation  used  in  coating 
the  Egyptian  obelisk  in  Central  Park  is  said  to  have  consisted  of  par- 
affine  containing  creosote  dissolved  in  turpentine,  the  creosote  being 
considered  efficacious  in  preventing  organic  growth  upon  the  stone. 
The  melting  point  of  the  compound  is  about  140°  F.  In  applying, 
the  surface  to  be  coated  is  first  heated  by  means  of  especially 
designed  lamps  and  charcoal  stoves,  and  the  melted  compound 
applied  with  a  brush.  On  cooling  it  is  absorbed  to  a  depth  depend- 
ent upon  the  degree  of  penetration  of  the  heat.  In  the  case  of  the 
obelisk  about  £  inch."  * 

A  soap  and  alum  solution  has  also  been  used  for  rendering  stone 
waterproof,  with  moderate  success. 

Ransome's  Process. — This  consists  in  applying  a  solution  of  silicate 
of  soda  or  potash  (water  glass)  to  the  surface  of  the  stone,  after  it 
has  been  cleaned,  with  a  whitewash  brush  until  the  surface  of  the 
stone  has  become  saturated.  After  the  stone  has  become  dry  a  solu- 
tion of  chloride  of  calcium  is  applied  freely  so  as  to  be  absorbed 
with  the  silicate  into  the  structure  of  the  stone.  The  two  solutions 
produce  by  double  decomposition  an  insoluble  silicate  of  lime,  which 
fills  the  pores  of  the  stone  and  binds  its  particles  together,  thus 
increasing  both  its  strength  and  weathering  qualities.  This  process 
has  been  used  to  a  considerable  extent  in  England,  and  is  perhaps 
the  most  successful  of  all  applications.  The  process  of  applying  the 
solutions  is  more  fully  described  in  "  Notes  on  Building  Construc- 
tion," Part  III.,  p.  78. 

***  Stones  for  Building  and  Decoration,"  pp.  399-400. 


CHAPTER  VI. 
CUT  STONEWORK. 


181.  To  properly  lay  out,  detail  and  specify  the  stonework  in  a 
building,  it  is  necessary  to  have  a  thorough  knowledge  of  the  differ- 
ent tools  and  processes  employed  in  cutting  and  dressing  the  stone 
and  of  the  different  ways  in  which  stone  is  used  for  walls,  ashlar  and 
trimmings. 

The  following  description  of  different  classes  of  work,  supple- 
mented by  critical  observation  in  the  stone  yard  and  at  the  building, 
should  give  one  a  good  idea  of  the  ordinary  methods  and  practices 
employed  in  this  country  : 

Stonework,  such  as  is  used  in  the  superstructure  of  buildings,  may 
be  divided  into  three  classes  :  Rubble,  Ashlar  and  Trimmings. 

182.  Rubble    Work  is  only  used  for  exterior  walls  in  places 
where  suitable  stone  for  cutting  cannot  be  cheaply  obtained.     There 
are  some  localities  which  furnish  a  cheap,  durable  stone  that  cannot 


Fig.  60  — Rubble,  Undressed,  Laid  at  Random. 

be  easily  cut,  such  as  the  conglomerates  and  slate  stones.  These 
stones  generally  split  so  as  to  give  one  good  face,  and  may  be  used 
with  good  effect  for  walls,  with  cut  stone  or  brick  trimmings. 

Fig.  60  shows  the  usual  method  of  building  a  rubble  wall  above 
ground.     After  the  wall  is  up  the  joints  are  generally  filled  flush  with 


CUT  STONEWORK. 


'5* 


mortar  of  the  same  color  as  the  stone,  and  a  raised  false  joint  of  red 
or  white  mortar  stuck  on,  to  imitate  ashlar.  Such  work  should  be 
specified  to  be  laid  with  beds  and  joints  undressed,  projections 
knocked  off  and  laid  at  random,  interstices  to  be  filled  with  spalls 
and  mortar.  If  a  better  class  of  work  is  desired,  the  joints  and  beds 
should  be  specified  to  be  hammer-dressed. 


Fig.  61. — Random  Rubble  with  Hammer-dressed  Joints  and  no  Spalls  on  Face. 

Fig.  6 1  shows  a  kind  of  rubble  work  sometimes  used  for  buildings, 
which  is  quite  effective  for  suburban  architecture.  It  should  be 
specified  to  have  hammer-dressed  joints,  not  exceeding  \  or  f  of  an 
inch,  and  no  spalls  on  face.  This  is 
generally  expensive  work. 

Fig.  62  shows  a  rubble  wall  with 
brick  quoins  and  jambs. 

Occasionally  small  boulders  or  field 
stone  are  used  for  the  walls  of  rustic 
buildings.  In  such  case  the  wall 
should  be  quite  thick,  with  a  backing 
of  split  stone,  to  hold  the  boulders, 
and  the  exact  manner  in  which  the 
wall  is  to  be  built  should  be  specified. 
There  are  several  kinds  of  rubble 
used  in  engineering  work,  but  the 
above  are  about  the  only  styles  used  in  buildings. 

183.  Ashlar. — The  outside  facing  of  a  wall,  when  of  cut  stone,  is 
called  ashlar,  without  regard  to  the  way  in  which  the  stone  is  finished. 
Ashlar  is  generally  laid  either  in  continuous  courses,  as  in  Figs.  63 
and  64,  or  in  broken  courses,  as  in  Fig.  68  ;  or  without  any  continu- 
ous horizontal  joints,  as  in  Figs.  65  and  66,  which  represent  broken 
ashlar.  Coursed  work  is  always  the  cheapest  when  stones  of  a  given 


Fig.  62. 


15* 


BUILDING  CONSTRUCTION. 


size  can  be  readily  quarried,  as  is  usually  the  case  with  sand  and 
limestones.  The  cheapest  ashlar  for  most  stones  is  that  which  is  cut 
into  i2-inch  courses,  with  the  length  of  the  stones  varying  from  18  to 


Fig.  63.— Coursed  Ashlar. 

24  inches.  When  the  stones  are  cut  30  inches  to  3  feet  in  length, 
and  with  the  end  joints  plumb  over  each  other,  as  in  Fig.  63,  the  cost 
is  considerably  increased,  and  if  this  kind  of  work  is  desired  it  should 
be  particularly  specified. 


Fig.  64.— Coursed  Ashlar. 


Fig.  63  is  regular  coursed  ashlar,  each  course  —  inches  in  height, 
and  with  plumb  bond.  When  the  courses  of  stone  are  of  different 
heights  it  is  called  irregular  coursed  ashlar. 


CUT  STONEWORK. 


'53 


A  form  of  ashlar  now  much  used  is  that  shown  in  Fig.  64,  in  which 
a  wide  and  narrow  course  alternate  with  each  other.  Six  and  14 
inches  make  good  heights  for  the  courses. 


/v 


/o 


V 


/V 


Fig.  65.— Broken  Ashlar  (Six  Sizes). 

Fig.   69   shows   regular   coursed   ashlar,  with    rustic    quoins   and 
plinth,  which  is  much  used  in  Europe. 

184.  Broken  Ashlar. — When  stones  of  uniform  size  cannot  be 


=[ 


Fig.  66.— Broken  Ashlar  (Three  Sizes). 


cheaply  quarried  the  stone  may  be  used  to  better  advantage  in 
broken  ashlar,  but  it  takes  longer  to  build  it,  and,  as  a  rule,  broken 
ashlar  costs  considerably  more  than  coursed  ashlar.  This  style  of 


i54  BUILDING  CONSTRUCTION. 

work  is  generally  considered  the  most  pleasing,  and,  when  done  with 
care,  makes  a  very  handsome  wall,  as  shown  by  the  half-tone  illustra- 
tion, Fig.  67.  It  is  generally  only  used  for  rock-face  work.  To  have 


Fig.  67.— Broken  Ashlar. 

the  best  appearance  n6  horizontal  joint  should  be  more  than  4  feet 
long,  and  several  sizes  of  stone  should  be  used.  Broken  ashlar  can 
be  more  quickly  laid,  and  at  less  expense,  if  the  stone  is  cut  to  cer- 
tain heights  in  the  yard,  so  that  only  one  ehd  joint  need  be  cut  at 
the  building. 


Fig.  68.— Random  Coursed  Ashlar. 

Fig.  65  is  made  up  of  stones  cut  4,  6,  8,  10,  12  and  14  inches  in 
height,  while  in  Fig.  66  only  three  sizes  of  stones  have  been  used. 
Fig.  65  would  probably  be  the  more  pleasing  of  the  two  if  executed. 


CUT  STONEWORK. 


155 


In  specifying  broken  ashlar  the  height  of  the  stone  to  be  used  should 
be  specified.  Broken  ashlar  is  sometimes  arranged  in  courses  from 
1 8  to  24  inches  high,  as  in  Fig.  68,  when  it  is  called  random  coursed 
ashlar.  It  looks  very  well  in  piers. 

185.  Quoins  and  Jambs. — The  stones  at  the  corner  of  a  build- 
ing are  called  the  quoins,  and  these  are  often  emphasized,  as  in 
Figs.  6 1  and  69.  They  should  always  be  equal  in  size  to  the  largest 
of  the  stones  used  in  the  wall.  The  stones  at  the  side  of  a  door  or 
window  opening  are  called  jambs.  Fig.  70  represents  cut  stone  win- 
dow jambs  in  a  rubble  wall.  A  portion  of  the  jamb  stones  should 
extend  through  the  wall  to  give  a  good  bond. 


Fig.  69. — Regular  Coursed  Ashlar. 

In  rubble  walls  the  quoins  and  jambs  are  often  built  of  brick,  as 
shown  in  Fig.  62. 

All  ashlar  work  should  have  the  bed  joints  perfectly  straight  and 
horizontal,  and  the  vertical  joints  perfectly  plumb,  or  the  appearance 
will  be  greatly  marred. 

Trimmings. — This  term  is  generally  used  to  denote  all  mouldings, 
caps,  sills  and  other  stonework,  except  ashlar.  The  trimmings  may 
be  pitched  off  on  their  face,  but  all  washes,  soffits  and  jambs  should 
be  cut  or  rubbed. 

STONECUTTING  AND  FINISHING. 

186.  That  the  architect  may  specify  correctly  the  way  in  which  he 
wishes  the  stone  finished  in  his  buildings,  it  is  necessary  that  he  be 
familiar  with  the  tools  used  in  cutting,  and  the  technical  names 
applied  to  different  kinds  of  finish. 

Stonecutting  Tools. — There  are  several  kinds  of  hammers 
used  by  masons  in  dressing  rubble,  and  also  a  variety  of  tools  used  in 
quarrying,  but  as  they  are  not  used  in  working  the  finished  stone  they 
will  not  be  described. 


i56 


BUILDING  CONSTRUCTION. 


The  Axe  or  Pean  Hammer,  Fig.  71,  has  two  cutting  edges.  It  is 
used  for  making  drafts  or  margin  lines  around  the  edge  of  the  stones, 
and  for  reducing  the  faces  to  a  level.  It  is  used  after  the  noint  on 
granite  and  other  hard  stones. 


Fig.  7°. 


Fig.  71. — Axe  or  Pean  Hammer. 


The  Tooth  Axe,  Fig.  72,  has  its  cutting  edges  divided  into  teeth, 
the  number  of  which  varies  with  the  kind  of  work  required.  It  is 
used  for  reducing  the  face  of  sandstones  to  a  level,  ready  for  the 
crandall  or  tool.  It  is  not  used  on  granites  and  hard  stones. 


Fig.  72.— Tooth  Axe. 

The  Bush  Hammer,  Fig.  73,  is  a  square  hammer,  with  its  ends 
(from  2  to  4  inches  square)  cut  into  a  number  of  pyramidal  points. 
It  is  used  for  finishing  the  surface  of  sand  and  limestones,  after  the 
face  of  the  stone  has  been  brought  nearly  to  its  place. 

The  Crandall,  Fig.  74,  is  a  malleable  iron  bar  about  2  feet  long, 
slightly  flattened  at  one  end,  through  which  is  a  slot  |  of  an  inch 
wide  and  3  inches  long.  Through  this  slot  are  passed  ten  double- 


CUT  STONEWORK.  15* 

headed  points  of  £-inch  square  steel,  about  9  inches  long,  which  are 
held  in  place  by  a  key.  Only  one  end  of  the  crandall  is  used,  and 
as  the  points  become  dull  they  can  be  taken  out  and  sharpened  or 


Fig.  73. — Bush  Hammer. 

the  ends  reversed.     The  instrument  is  used  for  finishing  sandstone 
after  the  surface  has  been  prepared  by  the  tooth  axe  or  chisel. 

The  Patent  Hammer,  Fig.  75,  sometimes  called  bush  hammer,  is. 
made  of  four,  six,  eight  or  ten  thin  blades  of  steel,  ground  to  an  edge 
and  bolted  together  so  as  to  form  a  single  piece.  It  is  used  for  fin- 


Fig.  74.— Crandall.  Fig.  75,— Patent  Hammer. 

ishing  granite  and  hard  limestones,  the  fineness  of  the  finish  being- 
regulated  by  the  number  of  blades  used. 

The  Point. — Fig.   76,   No.  4,  has  a  sharp  point,  and  is  used  in 
breaking  off  the  rough  surface  of  the  stone  and  reducing  it  to  a  plane, 


158 


B  UILDING  CONS TR  UCTION. 


ready  for  the  axe,  hammer  or  tool.  It  is  also  used  to  give  a  rough 
finish  to  stone  for  broach  work  and  also  for  picked  work.  No.  i, 
Fig.  76,  represents  the  tooth  chisel,  used  only  on  soft  stones ;  No.  2  a 
drove,  about  2  or  3  inches  wide  ;  Nos.  3,  7  and  8  different  forms  of 


di  LJ 


4  5 

Fig.  76- 


chisels  used  on  soft  stone.  No.  5  is  a  tool,  usually  from  3^  to  4$- 
inches  wide,  used  for  finishing  sandstone,  and  No.  6  is  a  pitching 
chisel,  used  as  in  Fig.  77. 

187.    Different   Kinds    of    Finish. — Rock-face  or  pitch-faced 
work  is  shown  in  Fig.  77,  the  face  of  the  stone  being  left  rough  as  it 


Fig.  77.— Rock-face  or  Pitch-face. 


Fig.  78.— Rock-face  with  Draft  Line. 


came  from  the  quarry,  with  the  joints  or  edges  "pitched  off"  to  a 
line  as  shown.  The  amount  of  projection  of  the  centre  of  the  stone 
beyond  the  plane  of  the  joints  should  be  specified.  The  ashlar  shown 
in  Fig.  67  is  "  rock-face." 

Rock-face   with   margin  lines  is  the  next  step  toward  finishing  a 
stone,  and  is  shown  in  Fig.  78.     The  margin  (often  called  draft  line) 


CUT  STONEWORK. 


'59 


is  cut  with  a  tool  chisel  in  soft  stones  and  with  an  axe  in  granite. 
Sometimes  only  the  angle  of  the  quoins  has  a  draft  line,  as  in  Fig.  79, 
when  it  is  called  "angle  draft."  Rock-face  ashlar  is  naturally 

cheaper  than  any  kind  of  dressed 
ashlar,  particularly  in  granite. 

Broached  Work. — The  surface 
of  the  stone  is  dressed  off  to  a 
level  surface,  with  continuous 
grooves  made  in  it  by  the  point. 
Fig.  80  shows  a  stone  with  margin 
or  draft  lines  and  broach  centre. 

Pointed  Work  (Figs.  81  and  82). 
— When  it  is  desired  to  dress  the 
face  of  a  stone  so  that  it  shall  not 
project  more  than  £  to  \  inch,  and 
where  a  smooth  finish  is  not 
required,  as  in  basement  piers,  etc., 
the  rock-face  is  taken  off  with  a 


Fig.  79.— Rock-face  with  Angle  Draft. 


point  and  the  surface  is  rough  or  fine  pointed,  according  as  the  point 
is  used  over  every  inch  or  half  inch  of  the  stone.  The  point  is  used 
more  for  dressing  hard  stones  than  soft  stones. 

Tooth-chiseled. — The  cheapest  method  of  dressing  soft  stones  is  by 
the  tooth  chisel,  which  gives  a  surface  very  much  like  pointed  work, 
only  generally  not  as  regular. 


11W1111S 


Fig.  80.— Broached  with  Tooled  Margin. 


Fig.  81.— Rough  Pointed. 


Tooled  work  is  done  with  a  flat  chisel  from  3^  to  4^  inches  wide, 
and  the  lines  are  continued  clear  across  the  width  of  the  piece,  as 
shown  in  Fig.  83.  When  well  done  it  makes  a  very  pretty  finish  for 
sandstone  and  limestone,  and  especially  for  moulded  work. 

Drove  work  is  much  like  tooled  work,  but  done  with  a  chisel  about 
2\  inches  wide  and  in  rows  lengthways  of  the  piece,  as  shown  in 
Fig.  84.  Drove  work  does  not  take  quite  as  much  time  as  tooled 
work,  and  hence  is  che-aper,  but  it  does  not  l6ok  as  well. 


160  BUILDING  CONSTRUCTION. 

Bush-hammered.— -This  finish  is  made  by  pounding  the  surface  of 
the  stone  with  a  bush  hammer,  leaving  it  full  of  points,  as  in  Fig.  87. 
It  makes  a  very  attractive  finish  for  the  harder  kinds  of  sand  and 
limestones,  but  ought  not  to  be  used  on  soft  stones. 

Crandalled  Work  (Fig.  85).— The  face  of  the  stone  is  dressed  all 
over  with  the  crandall,  which  gives  it  a  fine  pebbly  appearance  when 
thoroughly  done.  It  makes  a  sparkling  surface  for  red  sandstones, 


Fig.  8s.— Fine  Pointed. 


Fig.  83.-Tooled. 


and  is  used  more  than  any  other  finish  in  Massachusetts  for  sand- 
stones.    The  crandall  is  not  used  on  granite  and  other  hard  stones. 

Rubbed.— One  of  the  handsomest  methods  of  finishing  sand  and 
limestones  is  to  rub  their  surfaces  until  they  are  perfectly  smooth, 
either  by  hand,  using  a  smooth  piece  of  soft  stone  with  water  and 
sand  for  rubbing,  or  by  laying  the  stone  on  a  revolving  bed  called  a 
rubbing  bed.  When  the  stone  is  first  sawed  into  slabs  rubbing  is 


illl 

Fig.  85.—  Crandalled. 

Fig.  84. -Drove  Work. 

very  easily  and  cheaply  done,  so  that  rubbed  sandstone  ashlar  is 
often  as  cheap  as  rock-face  work  in  yards  where  steam  saws  are  used. 
The  saws  leave  the  stone  comparatively  smooth  and  suitable  for  the 
top  of  copings  and  unexposed  places.  Granites,  marbles  and  many 
limestones,  when  rubbed  long  enough,  take  a  high  polish. 

Picked  Work. — In  this  work  the  face  of  the  stone  is  first  leveled 
off  with  the  point  and  then  picked  all  over  as  though  a  woodpecker 


CUT  STONEWORK.  161 

had  picked  it.     Broken  ashlar  finished  in  this  way  has  a  very  pretty 
effect,  but  is  quite  expensive. 

Patent-hammered  or  Bush-hammered  (Fig.  86). — When  it  is  desired 
to  give  a  finished  surface  to  granite  and  the  hard  limestones  they  are 
first  dressed  to  a  rough  surface  with  the  point  and  then  to  a  medium 
surface  with  the  same  tool,  and  finally  finished  with  the  patent  ham- 
mer. The  fineness  of  the  finish  is  determined  by  the  number  of 


Fig.  86.— Patent-hammered.  Fig.  87.— Bush-hammered. 

blades  in  the  hammer,  and  the  work  is  said  to  DC  "six-cut,"  "eight- 
cut  "  or  "  ten-cut,"  according  as  six,  eight  or  ten  blades  are  used. 
Government  work  is  generally  ten-cut.  Eight-cut  is  mostly  used  for 
average  work,  and  for  steps  and  door  sills  six-cut  is  sufficiently  fine. 
The  architect  should  always  specify  the  number  of  blades  to  be  used 
when  the  work  is  to  be  finished  with^a  patent  hammer.  The  same 
finish  may  be  obtained  with  the  axe,  but  it  requires  much  more  time. 


Fig.  88.-Vermiculated.  Fig.  89.-Fish  Scale. 

Vermiculated  Work  (Fig.  88). — Stones  worked  so  as  to  have  the 
appearance  of  having  been  worked  by  worms.  It  is  generally  con- 
fined to  quoins  and  base  courses. 

Rusticated  Work. — This  term  is  now  generally  used  to  denote  sunk 
or  beveled  joints,  as  in  Figs.  69  and  90,  although  it  originally  referred 
to  work  honeycombed  all  over  on  the  face  to  give  a 'rough  effect,  as 
shown  in  Fig.  69. 


162 


BUILDING  CONSTRUCTION. 


Fish  Scale  or  Hammered  Brass  (Fig.  89).— Work  made  to  imitate 
hammered  brass,  and  done  with  a  tool  with  rounded  corners. 

Vermiculated  and  fish  scale  work  are  seldom  seen  in  this  country. 

188.  Laying  Out. — If  the  cost  of  the  stonework  must  be  con- 
sidered, the  architect  should  ascertain  from  some  reliable  local  stone 
dealer  the  most  economical  size  for  the  kind  of  stone  he  intends  to 
use,  and  lay  out  his  work  accordingly. 

Trimmings. — If  the  stonework  consists  merely  of  trimmings  for 
a  brick  building,  the  architect  or  his  draughtsman  must  first  ascertain 
the  exact  measurement  of  the  bricks  as  laid  in  the  wall,  and  the  stone 
should  be  figured  so  as  tfi  exactly  fit  in  with  the  brickwork,  otherwise 


Fig.  90.— Rusticated  Joints. 

the  bricks  will  have  to  be  split  where  they  come  against  the  stone, 
thereby  greatly  marring  the  looks  of  the  building.  Bond  stones  and 
belt  courses  built  into  a  pier  must  conform  exactly  to  the  size  of  the 
pier.  As  it  is  seldom  that  the  bricks  from  any  two  yards  are  of 
exactly  the  same  size,  the  exact  size  of  the  bricks  that  are  to  be  used 
must  be  taken,  as  even  a  variation  of  \  inch  often  makes  bad  work. 

189.  Drip  and  Wash. — Projecting  cornices,  belt  courses  and  other 
trimmings  should  have  sufficient  depth  that  they  will  balance  on  the 
wall,  and  all  projecting  stones  should  have  a  drip  as  near  the  top  of 
the  stone  as  possible,  to  prevent  the  water  from  dripping  over  the  rest 
of  the  cornice  and  down  on  the  wall.  Thus  in  a  cornice  such  as 
shown  in  Fig.  91  the  stone  should  be  cut  at  a  sharp  angle  at  Ay  so 
that  some  of  the  water  may  drop  off,  and  there  should  be  a  regular 
drip  at  B,  that  the  water  may  not  run  down  on  the  wall.  It  is  a 


CUT  STONEWORK. 


'63 


good  idea  tc  cut  a  drip  in  all  window  sills,  as  shown  in  Fig.  92.  In 
the  summer  dust  always  lodges  on  a  sill  or  projecting  ledge,  and  when 
it  rains  the  water  washes  the  dust,  which  often  contains  cinders,  over 
the  face  of  the  stonework  and  down  on  the  wall,  causing  both  to 
become  badly  streaked  and  often  unsightly. 

The  architect  will  find  that  if  he  is  careful  to  provide  drips  on  all 
mouldings  and  sills  his  buildings  will  remain  bright  and  clean  for  a 


Fig.  92. 

much  longer  time  than  would  otherwise  be  the  case.  It  is  even  bet- 
ter to  change  the  profile  of  the  moulding,  if  necessary,  to  provide  the 
drip,  as  the  most  beautiful  moulding  looks  unsightly  when  streaked 
and  stained  with  dirty  water. 

Washes. — The  top  of  all  cornices,  oelt  courses,  capitals,  etc.,  should 
be  cut  so  as  to  pitch  outward  from  the  wall  line,  as  shown  in  Fig.  91. 


Fig.  93. — Top  of  Belt  Course.  * 

If  the  top  is  left  level,  the  rain  water  falling  upon  it  will,  in  time,  dis- 
integrate the  mortar  in  the  joint  above  and  finally  penetrate  into  the 
wall.  Surfaces  beveled  in  this  way  are  called  washes. 

When  the  face  of  a  wall  is  broken  with  pilasters,  or  the  windows 
are  recessed,  the  wash  on  the  belt  courses  should  be  cut  to  fit  the 
plan  of  the  wall  above,  as  shown  in  Fig.  93. 


i64 


BUILDING  CONSTRUCTION. 


190.  Relieving  and  Supporting  Lintels.— [A  lintel  is  the 
stone  which  covers  a  door  or  window  opening,  and  which,  therefore, 
acts  as  a  beam.  They  are  often  designated  by  stonecutters  by  the 


Fig.  94- 

term  "cap."]  When  it  is  necessary  to  use  rather  a  long  lintel  in  a 
stone  wall  the  ashlar  above  the  lintel  may  be  arranged  so  as  to  relieve 
the  lintel  of  some  of  the  weight,  as  shown  in  Fig.  94.  If  the  wall 
above  the  lintel  is  of  brick  a  relieving  arch  may  be  turned,  but  this 
generally  detracts  from  the  appearance  of  the 
building,  and  the  best  way  to  strengthen  the 
lintel,  when  the  length  does  not  exceed  6  feet, 
is  to  let  it  rest  on  a  steel  angle  bar  the  full 
length  of  the  cap,  as  shown  in  Fig.  95.  When 
the  width  of  the  opening  is  more  than  6  feet 
the  lintel  should  be  supported  by  steel  beams, 
as  shown  in  Figs  96  and  97.  A  single  beam, 
as  in  Fig.  96,  may  be  used  where  only  the 
weight  of  the  lintel  and  its  load  is  to  be  sup- 
ported, and  two  or  more  beams  where  the 
whole  thickness  of  the  wall  and  also  the  floor 
joist  must  be  supported. 

When  the  lintel  is  the  full  thickness  of  the 
wall,  and  any  steel  support  is  undesirable,  the 
strength  of  the  lintel  may  be  increased,  if  of  a  stratified  stone,  by  cut- 
ting the  stone  so  that  the  layers  will  be  on  edge,  like  a  number  of 
planks,  placed  side  by  side.  The  ancient  Greeks  and  Romans  often 
cut  their  lintels  in  this  way,  and  apparently  for  this  reason. 


Fig.  95 


CUT  STONEWORK. 


165 


In  placing  windows  in  a  brick  or  stone  wall  the  Designer  should 
be  careful  to  arrange  them  so  that  they  will  not  come  under  a  pier. 
This  is  not  apt  to  happen  in  the  front  of  a  building,  but  it  sometimes 
happens  on  a  side  or  rear  wall,  where  the  windows  are  placed  to  suit 
the  interior  arrangement  and  without  regard  to  the  external  effect. 

If  a  door  or  window  must  be  placed  under  a  pier  or  high  wall  steel 
beams  should  be  used  to  support  the  wall  above  and  also  the  lintel. 
Many  broken  lintels  are  evidence  of  a  too  frequent  neglect  of  this 
precaution. 

Another  point  that  should  be  carefully  considered  in  laying  out  the 
stonework  is  building  the  ends  of  caps  and  sills  into  piers.  If  the 


Fig.  96- 


Fig.  97.— 96-inch  Steel  Plate  Riveted  to  Beams. 


pier  extends  through  -several  stories  the  joints  will  all  be  slightly  com- 
pressed and  the  masonry  will  settle  some,  and  if  the  ends  of  the  caps 
and  sills  of  the  adjoining  windows  are  solidly  built  into  the  piers  they 
are  very  apt  to  be  broken  as  the  pier  settles. 

The  best  arrangement  is  to  keep  the  caps  and  sills  back  from  the 
face  of  the  pier,  and  either  build  pilasters  against  the  pier  to  receive 
the  caps  and  sills,  as  shown  at  A,  Fig.  98,  or  else  build  the  ends  of 
the  stones  into  the  pier  in  such  a  way  that  they  can  give  a  little. 
When  the  cap  is  back  from  the  face  of  the  pier  this  can  easily  be 
done. 

Lintels  should  have  a  bearing  at  each  end  of  from  4  to  6  inches, 
according  to  the  width  of  the  opening.  It  is  better  not  to  build  the 
-ends  into  the  wall  more  than  is  necessary  to  give  a  sufficient  bearing. 

Composite  Lintels. — Very  often  it  is  desired  to  place  a  stone  lintel 
over  a  store  window  10  or  12  feet  wide.  To  procure  such  a  lintel  in 
one  piece  is,  in  many  places,  impracticable,  and  it  is  therefore 


1 66 


B  UILDING  CONS  TR  UC  TION. 


necessary  to  build  the  lintel  up  in  pieces.  When  such  is  the  case  at 
least  three  stones  should  be  used,  and  the  end  joints  should  be  cut 
as  shown  in  Fig.  99.  Cutting  the  stones  in  this  way  binds  them 
together  better,  and  also  gives  the  appearance  of  being  self-support- 
ing. A  greater  number  of  stones,  say  five  or  seven,  may  be  used  if 
preferred,  but  the  joints  should  be  cut  in  the  same  way.  Such  lin- 


•/  /.".'.*".  "..•  •  :.-  ••  '• '.  • 


I  '     I 


T~1 — I — T 


1     i     l 


tels  should  always  be  supported  by  steel  beams,  either  as  shown  in 
Fig.  96  or  Fig.  97. 

191.  Sills. — A  "sill  "  is  the  piece  of  stone  which  forms  the  bot- 
tom of  a  window  opening  in  a  stone  or  brick  wall.  Doorsteps  or 
thresholds  are  also  often  called  "sills." 

A  slip  sill  is  a  sill  that  is  just  the  width  of  the  opening,  and  is  not 
built  into  the  wall. 

Lug  sills  are  those  which  have  flat  ends,  built  into  the  wall,  as 
shown  in  Fig.  100. 


CUT  STONEWORK. 


167 


All  sills  should  be  cut  with  a  wash  of  at  least  \  inch  to  5  inches  in 
depth,  and  if  the  ends  are  to  be  built  into  the  wall  they  should  be 
cut  as  shown  in  Fig.  100.  In  some  parts  of  the  country  the  sills  are 
cut  with  a  straight  beveled  surface  the  full  length  of  the  stone,  and 
where  they  are  built  into  the  wall  the  bricks  are  cut  to  fit  the  stone. 
This  is  not  a  good  method,  as  the  water  running  down  the  jamb  and 


T 


T 


Fig.  99. 


striking  the  sill  is  apt  to  enter  the  joint  between  the  brick  and  stone, 
and  the  slanting  surface  also  offers  an  insecure  bearing  for  the  brick. 
Slip  sills  are  cheaper  than  lug  sills,  but  they  do  not  look  as  well, 
and  there  is  also  danger  of  the  mortar  in  the  end  joint  being  in  time 
washed  out. 

Slip  sills,  however,  are  not  likely  to  be  broken  by  any  settlement  in 
the  brickwork,  and  for  this  reason  many  architects  prefer  to  use  them 
for  the  lower  openings  in  heavy  buildings  and 
also  for  very  wide  openings. 

Lug  sills  should  not  be  built  into  the  jambs 
more  than  4  inches,  and  should  only  be 
bedded  at  the  ends  when  setting. 

192.  Arches. — Stone  arches  are  very  fre- 
quently used  both  in  stone  and  brick  build- 
ings. They  may  be  built  in  a  great  variety  of 
styles,  and  with  either  circular,  elliptical  or 
pointed  soffits.  The  method  of  calculating 
the  stability  of  a  stone  arch  is  the  same  as  for  a  brick  arch,  but  a 
stone  arch  being  constructed  in  larger  pieces,  the  mortar  in  the  joints 
adds  but  very  little,  if  any,  to  the  stability  of  the  arch,  and  a  stone 
arch  of  the  same  size  as  a  brick  arch  is  rather  more  liable  to  settle  or 
crack  than  the  brick  arch,  and  should  be  constructed  with  greater 
care.  The  method  of  calculating  the  stability  of  arches  is  given  in 
Chapter  VIII.  of  the  Architects  and  Bunders  Pocket  Book.  In 
block  stone  arches  each  block,  or  "voussoir,"  should  always  be  cut 
wedge-shape  and  exactly  fitted  to  the  place  it  is  to  occupy  in  the 


1 68 


BUILDING  CONSTRUCTION. 


arch.  The  joints  between  the  voussoirs  should  be  of  equal  width  the 
entire  depth  and  thickness  of  the  arch,  that  the  bearing  may  be  uni- 
form over  the  entire  surface.  The  thickness  of  the  joint  will  depend 
somewhat  upon  the  character  of  the  stonework.  In  finely  dressed 
work  -fa  of  an  inch  is  the  usual  thickness,  while  in  rock-face  work  it 
is  seldom  made  less  than  f  of  an  inch.  One-fourth  .of  an  inch,  how- 
ever, is  all  that  should  be  allowed  in  first-class  work. 

The  joints  should  also  radiate  from  the  centre  from  which  the 
intrados  is  struck,  or,  in  the  case  of  an  elliptical  arch,  they  should  be 
at  right  angles  to  a  tangent  drawn  to  the  intrados  at  that  point.  See 
Fig.  1 06,  Section  198. 

The  back  of  the  arch  may  either  be  concentric  with  the  intrados, 
or  the  ring  may  be  deeper  in  the  centre  than  at  the  sides. 


xtrados. 


Fig.  ,«. 

The  most  common  stime  arch  is  that  shown  in  Fig.  101,  the  arch 
ring  being  of  equal  depth  and  the  voussoirs  all  of  the  same  size,  and 
rock-face,  with  pitched  joints.  Occasionally  the  voussoirs  are  cut 
with  a  narrow  margin  draft,  as  shown  at  B.  When  the  springing 
line  of  an  arch  is  below  the  centre,  as  shown  in  Fig.  101,  the  arch  is 
said  to  be  "stilted,"  the  distance  6"  being  called  the  "stilt."  Stilted 
arches  are  very  common  in  Romanesque  architecture. 

A  semicircular  arch  is  one  of  the  best  shapes  for  supporting  a  wall. 
It  must,  however,  have  sufficient  abutment,  and  the  depth  of  the  arch 
ring,  or  the  distance  from  the  intrados  to  the  extrados,  in  feet,  should 
be  at  least  equal  to  0.2  +  y  radius  +  half  span 

4 

Arches  used  in  connection  with  coursed  ashlar,  especially  in 
Renaissance  buildings,  often  have  the  voussoirs  cut  to  the  shapes 
shown  in  Figs.  102  and  103. 


CUT  STONEWORK. 


169 


Such  arches  are  of  course  more  expensive  than  arches  with  the 
intrados  and  extrados  concentric,  as  there  is  more  waste  to  the  stone 
and  more  patterns  are  required.  They  ha\  e  a  more  pleasing  appear- 
ance, however,  and  are  also  stronger.  Voussoirs  of  the  shape  shown 
in  Fig.  103  must  be  cut  with  extreme  accuracy. 

In  dividing  the  arch  into  v.oussoirs  it  should  be  remembered  that, 
as  a  rule,  narrow  voussoirs  are  more  economical  of  material,  but  more 
expensive  in  point  of  labor. 

In  most  arches  the  width  of  the  voussoirs  at  the  bottom  is  about 
three-eighths  of  the  width  of  the  ring,  although  they  may  vary  from 
one-fourth  to  one-half. 

Very  often  two  voussoirs  are  cut  from  one  stone,  with  a  false  joint 
cut  in  the  centre.  This  is  done  generally  for  economy,  although  in 


Fig.  102. 


Fig  103. 


some  cases  it  may  add  to  the  stability  of  the  arch.  Generally  the 
arch  is  divided  into  an  uneven  number  of  voussoirs,  so  as  to  give  a 
keystone,  the  voussoifs  being  laid  from  each  side  and  the  keystone 
fitted  exactly  after  the  other  stones  are  set.  Except  that  it  is  more 
convenient  for  the  masons  there  appears  to  be  no  necessity  of  having 
a  keystone,  and  the  author  has  been  informed  that  Sir  Gilbert 
Scott  always  used  an  even  number  of  voussoirs,  believing  that 
thereby  the  danger  of  the  voussoirs  cracking  was  decreased. 

193.  Label  Mouldings. — In  nearly  all  styles  of  architecture  the 
better  class  of  buildings  have  the  arch  ring  moulded.  In  Gothic  and 
Romanesque  work  a  projecting  moulding  called  a  "label  mould"  is 
generally  placed  at  the  back  of  the  arch.  When  not  very  large  it 
may  be  cut  on  the  voussoirs,  but  usually  it  is  made  a  separate  course 
of  stone,  as  shown  in  Fig.  104.  When  this  is  the  case  the  depth  of 
the  arch  ring  without  the  label  mould  should  be  sufficient  for  stability. 


i7o  BUILDING  CONSTRUCTION. 

The  label  mould  may  be  cut  in  pieces  of  the  same  length  as  the  vous- 
soirs,  or  the  joints  may  be  made  independent  of  those  in  the  arch. 

194.  Built-up  Arches. — Large  arches,  especially  those  which 
show  on  both  sides  of  the  wall,  are  often,  for  the  sake  of  economy, 
built  of  several  courses  of  stone,  jointed  so  as  to  give  the  appearance 
of  solid  voussoirs.  Fig.  104  shows  the  manner  in  which  many  of  the 
large  arches  designed  by  the  late  H.  H.  Richardson  were  constructed. 
Every  alternate  pair  of  voussoirs  should  be  tied  together  by  galva- 
nized iron  clamps. 


Fig.  104. 


195.  Backing  of  Stone  Arches. — The  arches  generally  seen 
in  the  fronts  of  buildings  are  usually  only  about  6  inches  thick,  and 
are  backed  with  brick  arches.     The  brick  arch  should  be  of  the  same 
shape  as  the  stone  arch,  and  the  bricks  should  be  laid  in  cement 
mortar,  so  that  there  may  be  no  settlement  innhe  joints.     The  back- 
ing should  be  well  tied  to  the  stonework  by  galvanized  iron  clamps. 

196.  Relieving  Beams  Over  Arches. — Very  often  arches  are 
used  for  effect  in  places  where  sufficient  abutments  cannot  be  pro- 
vided to  resist  the  thrust  of  the  arch.     In  such  cases  one  or  more 
steel  beams  should  be  placed  in  the  wall  just  above  the  arch,  with 
the  ends  resting  over  the  vertical  supports  and  an  empty  joint  left 
beneath  the  centre  of  the  beams.     The  wail  above  can  then  be  built 
on  these  beams,  leaving  the  arches  with  only  their  own  weight  to  sup- 
port.    The  additional  weight  which  the  beams  carry  to  the  abut- 
ments also  greatly  increases  their  resistance  to  a  horizontal  thrust. 
The  beams  should  also  be  provided  with  anchors  at  their  ends,  with 
long  vertical  rods  passing  through  them,  to  tie  the  wall  together. 


CUT  STONEWORK. 


171 


Wherever  segmental  arches  are  used  it  is  always  a  safe  precaution 
to  place  steel  rods  back  of  them  to  take  up  the  thrust  of  the  arch 
while  the  mortar  in  the  abutments  is  green. 

197.  Support  for  Spandrels.— Wherever  arches  are  used  in 
groups  care  must  be  exercised  in  laying  out  the  springing  stones  to 
give  a  level  support  for  the  spandrels.  Thus  where  two  arches  come 
together,  as  at  A,  Fig.  105,  if  the  first  voussoir  is  cut  to  the  shape  of 
the  arch  on  the  back  a  small  wedge-shaped  piece  of  stone  would  be 
required  to  fill  the  space  between  the  first  pair  of  voussoirs.  The 
weight  of  the  wall  above  coming  on  this  wedge  might  be  sufficient  to 
force  the  voussoirs  in  and  seriously  mar  the  appearance  of  the  arch, 
as  well  as  causing  cracks  in  the  ashlar  above.  This  danger  may  be 


one 
piece. 


Fig.  105.  „ 

overcome  by  cutting  the  lower  stone,  a  a,  in  one  piece  for  both  arches 
and  extending  the  voussoir,  b,  to  a  vertical  joint  over  the  centre  of  the 
pier.  This  gives  a  level  bearing  for  the  lower  stone  in  the  spandrel 
and  effectually  prevents  any  pushing  in  of  the  voussoirs. 

Another  case  very  similar  to  this  often  occurs  where  the  back  of 
an  arch  comes  almost  to  the  corner  of  the  wall  or  projection,  as 
shown  at  B.  If  the  distance  between  the  back  of  the  arch  and  the 
angle  of  the  wall  is  less  than  8  inches  the  lower  voussoir  should  be  cut 
the  full  width  of  the  pier,  as  shown  in  the  illustration. 

198.  Elliptical  Arches.— Arches  built  either  in  the  form  of  an 
ellipse  or  oval,  or  pointed  at  the  centre  and  elliptical  at  the  springing, 
are  often  used  for  architectural  effect  in  buildings,  although  very 
seldom  in  engineering  works.  Such  arches  are  very  liable  to  either 
open  at  the  centre  and  "  kick  up  "  at  the.haunches,  or  to  fail  by  the 
centre  voussoirs  being  forced  down.  An  elliptical  arch,  especially 
if  very  flat,  is  undesirable  for  spans  of  over  8  feet,  and  should  never 


172 


BUILDING  CONSTRUCTION. 


be  used  without  ample  abutments  unless  beams  are  placed  above  the 
arch  as  described  in  Section  196. 

The  joints  of  an  elliptical  arch  should  be  exactly  normal  (at 
right  angles)  to  the  curve  of  the  soffit.  If  the  line  of  the  soffit 
is  not  a  true  ellipse,  but  is  made  up  of  circular  arcs  of  different 
radii,  the  joints  in  each  portion  of  the  arch  should  radiate  from 
the  corresponding  centre.  Fig.  106  shows  an  easy  method  for 
laying  out  the  joints  where  the  curve  of  the  soffit  is  a  true 
ellipse.  Let  Mlt  M%,  M3,  etc.,  be  points  on  the  ellipse  from 
which  it  is  desired  to  draw  the  joints.  Draw  tangents  to  the  ellipse 
at  the  points  A  and  B  intersecting  at  C.  Draw  the  lines  AB  and 
OC.  Draw  lines  from  J/a,  J/2,  M3,  etc.,  perpendicular  to  OA  and 
intersecting  OC  at  Z0  Z2,  -£3,  etc.  From  these  points  draw  lines 
perpendicular  to  A£,  intersecting  OA  at  N^,  7V2,  JV3,  etc.  Lines 
drawn  through  JV-1M1,  NZMZ,  etc.,  will  then  be  normal  to  the  curve 
and  give  the  joints  desired. 


° 


N7 


Fig.  106. 


199.  Flat  Arches.  -Shallow  flat  arches  of  stone,  although  some- 
times pleasing  to  the  eye,  are  very  objectionable  constructionally.  If 
a  flat  arch  must  be  used,  to  be  self-supporting  it  should  be  of  such 
height  that  a  segmental  arch  of  proper  size  can  be  drawn  on  its  face, 
as  indicated  by  the  dotted  lines  in  Fig.  107.  Even  then  it  is  desir- 
able to  drop  the  keystone  about  i  inch  below  the  soffit  line,  so  as  to 
wedge  the  voussoirs  tightly  together.  An  arch  such  as  is  shown  in 
Fig.  107  might  be  safely  used  for  a  span  of  5  feet,  but  with  great 
caution  for  larger  spans.  The  strength  of  such  an  arch  may  be 
increased  by  "joggled"  'joints,  that  is,  notching  one  stone  into  the 
other,  as  shown  by  the  dotted  lines  at  a.  Such  joints,  however,  are 
quite  expensive. 


CUT  STONEWORK. 


173 


Very  shallow  flat  arches,  such  as  is  shown  in  Fig.  108,  should  be 
cut  out  of  one  piece  of  stone,  so  as  to  be  in  reality  a  lintel  with  false 
joints  cut  on  its  face.     The  ends  of  the  lintel  should  hav«  a  bearing 
__^_^_^_^__^_^_^      on  the  wall  of  6  inches,  as  shown 
by   the   dotted    lines,   the    face 
being    cut    away    for    about    2 
inches   in    depth    and   veneered 
with   brick.     If    this   method  is 
too  expensive  the  lintel  might  be 
cut   in    three    pieces    and    sup- 
ported by  a  heavy  angle  bar,  as 
shown  in  Fig.  95. 

Very  long  lintels  are  often 
made  in  the  form  of  a  flat  arch  (see  Section  190),  but  are,  or  should 
be,  always  supported  by  steel  beams  or  bars. 

Rubble  Arches. — Arches  are  sometimes  built  of  rubble  stones. 
The  stones  should  be  long  and  narrow  and  roughly  dressed  to  a 
wedge  shape.  They  should  be  built  in  cement  mortar,  as  they 
depend  largely  upon  the  strength  of  the  mortar  for  their  stability. 


Fig.  108. 

2OO.  Centres. — All  arches,  whether  of  stone  or  brick,  should  be 
built  on  wooden  centres  made  to  exactly  fit  the  curve  of  the  arch  and 
carefully  set.  The  centres  should  have  ample  strength  to  support 
the  weight  of  the  arch  and  much  of  the  wall  above,  as  it  is  unde- 
sirable to  put  any  weight  on  the  arch  until  the  mortar  in  the  joints 
has  become  hard.  Centres  are  usually  made  with  two  ribs  cut  out  of 
plank  and  securely  spiked  together,  and  the  bearing  surface  formed 
of  cross  pieces  about  1x2  inches  in  size  nailed  to  the  top  of  the  ribs, 
as  shown  in  Fig.  109.  The  ribs  forming  the  supports  for'  the  cross 
pieces  should  be  placed  under  each  edge  of  the  arch,  and  if  the 
depth  of  the  arch  exceeds  12  inches  three  ribs  should  be  used.  The 
centre  should  be  supported  on  wooden  posts  resting  on  blocks  set  on 
the  sill  or  some  sufficient  support  below.  It  should  not  be  removed 
until  the  mortar  in  the  arch  joints  has  had  ample  time  to  set. 


i74  BUILDING  CONSTRUCTION. 

Centres  for  spans  of  considerable  extent  are  framed  together  with 
heavier  timbers  and  in  a  variety  of  ways.  The  general  method  is 
shown  by.  Fig.  no,  which  represents  a  centre  for  a  lo-foot  span. 
The  framework,  indicated  by  the  straight  pieces,  is  made  of  6x6  or 
4x8  timbers,  and  to  these  are  spiked  pieces  of  plank  cut  to  the  out- 
line of  the  arch.  The  cross  pieces  are  then  nailed  to  the  top  edge  of 
the  planks,  as  in  Fig.  109.  Such  a  centre  should  have  a  support 
under  the  middle  as  well  as  at  the  sides.  As  the  centres  are  only 


Fig.  109. 

required  for  temporary  use,  architects  generally  allow  the  carpenter 
to  construct  them  as  he  deems  best,  but  the  superintendent  should 
satisfy  himself  that  they  are  of  ample  strength  and  well  supported 
before  the  masons  commence  building  the  arch. 

MISCELLANEOUS  TRIMMINGS. 

201.  Columns  not  exceeding  8  feet  in  height  usually  have  the 
shaft  cut  in  one  piece  and  the  caps  and  bases  in  separate  pieces.  For 
columns  of  greater  height  it  is  generally  necessary  to  build  the  shaft 
of  several  pieces.  The  joints  between  the  cap  and  base  and  the 
shaft,  and  between  the  different  stones  of  the  shaft,  should  be  dressed 
perfectly  true  to  the  axis  of  the  column  and  to  a  true  plane,  so  that 


CUT  STONEWORK. 


175 


the  pressure  will  be  evenly  distributed  over  the  whole  area  of  the 
joint.  Nothing  but  cement  mortar  should  be  used  in  these  joints, 
and  the  outer  edge  of  the  joint  for  £  of  an  inch  from  the  face  should 
be  left  empty  to  prevent  the  outer  edges  chipping  off. 


Fig.  no. 

If  the  column  is  built  against  a  wall,  the  pieces  from  which  the 
cap  and  base  are  cut  should  either  extend  into  the  wall  or  be  secured 
by  galvanized  iron  clamps. 

Entablatures  spanning  porch  openings,  etc.,  may  either  be  cut  from 
one  piece  of  stone,  or,  if  of  considerable  height,  of  several  pieces. 

Fig.  in  shows  a  common  method  of 
building  up  an  entablature,  the  corona  and 
facia  being  in  still  another  course  above 
those  shown.  When  jointed  as  in  the  fig- 
ure the  bottom  joint  should  not  be  filled 
with  mortar  except  at  the  ends. 

The  various  stones  composing  the  cornice 
and  entablature  should  be  well  tied  together 
with  iron  clamps,  and  especially  at  all 
external  corners.  It  is  also  a  good  idea  to 
tie  the  cornices  of  porches  to  the  building 
by  long  rods  built  inside  the  mason  work 


Fig.  in. 


to  prevent  the  porch  from  "  pulling  away  "  from  the  wall. 

202.  Copings. — All  walls  not  covered  by  the  roof  should  be 
capped  by  a  wide  stone  called  the  coping.  Horizontal  copings  should 
be  weathered  on  top  and  have  a  drip  at  the  bottom  edge,  as  shown  at 
<C,  Fig.  112.  The  width  of  the  coping  should  be  about  3  inches 
greater  than  that  of  the  wall. 


i76 


BUILDING  CONSTRUCTION. 


Gable  copings  do  not  require  a  weathering  on  top,  but  they  should 
project  about  i£  inches  from  the  face  of  the  wall,  and  should  have  a 
sharp  outer  edge,  so  that  the  water  will  not  run  in  against  the  wall. 
As  the  weight  of  the  coping  has  a  tendency  to  cause  it  to  slide  on  the 
wall,  it  should  be  well  anchored  to  the  wall,  either  by  bonding  some 
of  the  stones  into  the  wall,  or  by  long  iron  anchors.  The  bottom 
stone,  sometimes  called  the  "kneeler,"  should  always  be  bonded 
well  into  the  wall  with  a  horizontal  bed  joint,  as  shown  at  Ky 
Fig.  112.  About  once  in  every  6  feet  in  height  a  short  piece  of  cop- 
ing should  be  cut  so  as  to  bond  into  the  wall  as  at  L.  Gable  copings 
sometimes  have  the  part  which  rests  on  the  wall  cut  in  steps,  so  that 
each  stone  has  a  horizontal  bearing.  This  method,  however,  is  very 


Fig.   112. 

expensive,  unless  the  coping  is  cut  in  very  short  pieces,  and  this  is 
objectionable  on  account  of  the  number  of  joints  required. 

As  a  rule  copings  should  be  in  as  long  stones  as  possible  to  avoid 
joints  which  admit  the  wet.  Horizontal  coping  stones  are  often 
clamped  together  at  their  ends  to  prevent  their  getting  out  of  place 
sideways. 

203.  Stone  Steps  and  Stairs.— These  should  always  be  built 
of  some  hard  stone,  preferably  granite,  and  should  have  a  solid  bear- 
ing. Outside  steps  generally  rest  on  a  wall  at  each  end,  and  if  more 
than  6  feet  long  should  have  a  support  at  the  centre.  Each  step 
should  rest  on  the  back  of  the  one  below  at  least  \\  inches.  Steps 
to  outside  entrances  should  pitch  outward  about  \  inch.  Steps  are 
much  more  comfortable  when  cut  with  a  nosing,  but  owing  to  the 
increased  expense  this  is  only  done  in  costly  buildings. 


CUT  STONEWORK.  I77 

Stone  stairs  may  be  built  with  only  one  end  supported.  In  Euro- 
pean buildings,  and  many  of  our  Government  buildings,  the  stairs 
are  constructed  as  shown  in  Fig.  113,  either  with  or  without  nosings. 
One  end  of  the  steps  is  solidly  built  into  the  wall,  and  each  step  is 
supported  by  the  one  below,  owing  to  the  way  in  which  they  are  cut. 
The  bearing  of  one  step  on  the  other  should  not  be  less  than  that 
shown  in  the  figure.  The  bottom  step  must  obviously  be  well  sup- 
ported its  full  length,  as  it  has  to  sustain  nearly  the  full  weight  of  the 
stairs.  The  steps  are  usually  cut  with  a  triangular  cross  section  as 
shown,  as  it  is  less  expensive  and  reduces  the  weight  of  the  stairs, 
besides  giving  a  pleasing  appearance  from  below. 

The  railing  is  generally 
of  iron,  doweled  into  the 
ends  of  the  steps. 

The  laying  out  and 
detailing  of  other  stone 
trimmings  will  be  gov- 
erned by  the  principles 

Fig.  113. 

above  noted. 

204.  Ashlar. — Laying  Out. — After  the  kind  and  size  of  ashlar  to 
be  used  has  been  determined  upon  the  draughtsman  should  show  each 
piece  of  ashlar  on  the  elevation  drawings  if  coursed  ashlar  with  plumb 
bond  is  to  be  used,  and  stones  of  particular  lengths  desired.  If  there 
are  piers  on  the  outside  of  the  building  a  section  drawing  should  be 
made  showing  how  the  stone  in  the  pier  is  to  be  bonded  with  the  rest 
of  the  wall. 

For  all  public  buildings  and  most  office  and  business  blocks  it  is 
generally  best  to  show  every  stone  on  the  plans  unless  broken  ashlar 
is  to  be  used,  when  the  labor  would  be  wasted.  As  a  rule,  in  ordi- 
nary stone  dwellings  and  in  fact  most  stone  buildings,  either  broken 
ashlar  is  used  or  coursed  ashlar  of  irregular  lengths,  in  which  case  it 
is  not  necessary  to  indicate  the  ashlar  on  the  elevation  drawings, 
except  to  show  the  height  of  the  courses,  if  coursed  ashlar  is  used. 
When  broken  ashlar  is  used  only  the  quoins  and  jambs  need  be  shown, 
and  a  small  piece  of  ashlar  indicating  the  kind  of  work  desired,  as  it 
would  be  almost  impossible  for  the  masons  to  carefully  follow  a  draw- 
ing of  broken  ashlar. 

Thickness  of  Ashlar. — Broken  ashlar,  and  coursed  ashlar  not 
exceeding  12  inches  in  height,  generally  varies  from  4  to  8  inches  in 
thickness,  and  averages  6  inches.  The  different  courses  should  vary 
in  thickness,  as  shown  in  Fig.  117,  it  being  better  to  have  one  course 


I78  BUILDING  CONSTRUCTION. 

4  inches  thick  and  the  next  8  inches  than  to  have  all  6  inches.  No 
ashlar,  however,  should  be  less  than  4  inches  in  thickness,  even  if  of 
marble.  Ashlar  laid  in  alternating  high  and  low  courses,  as  6  inches 
and  14  or  20  inches,  should  be  cut  so  that  the  low  courses  will  be  at 
least  8  inches  thick  and  the  high  courses  4  inches  thick,  and  each 
stone  in  the  latter  courses,  when  18  inches  or  more  in  height,  should 
have  at  least  one  iron  anchor  extending  through  the  wall. 

Fig.  114  shows  the  form  of 
anchor  generally  used.  The 
high  courses,  when  of  sandstone 
or  limestone,  are  generally 
sawed  of  a  uniform  thickness. 

Joints. — It  is  important  that 
the  surface  of  each  stone  shall  be  "out  of  wind,"  that  is,  a  true 
plane,  and  square  to  the  bed  and  end  joints. 

The  bed  joints  should  be  full  and  square  to  the  face  and  not 
worked  hollow,  as  in  Fig.  115,  as  with  hollow  joints  the  least  settle- 
ment in  the  mortar  will  throw  the  whole  pressure  on  to  the  edge  of 
the  stone  at  C,  and  cause  a  "spall"  or  pieces  to  splinter  off,  which 
ruins  the  appearance  of  the  building,  and,  moreover,  causes  a  sus- 
picion as  to  its  safety.  Stonecutters  are  very  apt  to  work  the  joints 
hollow  and  the  back  of  the  joint  slack,  as  in  Fig.  116,  as  it  requires 


Fig.  114. 


Fig.  116. 

much  less  labor  than  to  dress  the  joint  evenly,  and,  unless  carefully 
looked  after,  will  cut  the  stone  that  way  in  nearly  nine  cases  out  of 
ten.  If  the  back  of  the  joint  is  left  slack  and  underpinned,  as  in 
Fig.  1 1 6,  the  stone  is  then  supported  only  at  the  front  and  back,  and 
liable  to  break  in  the  middle,  as  shown.  Of  course,  in  a  wall  not 
exceeding  20  feet  in  height,  the  danger  arising  from  imperfect  joints 
is  not  as  great  as  in  a  wall  of  six  or  more  stories.  The  higher  the 
wall  the  more  carefully  should  the  joints  be  cut.  It  is  also  desirable 
that  the  joints  should  not  be  convex. 


CUT  STONEWORK. 


Bondt 


For  very  heavy  masonry,  as  in  the  basement  or  first  story  of  tall 
buildings,  it  is  desirable  to  use  rusticated  joints  (see  Fig.  90),  as  with 
such  joints  there  is  less  chance  for  the  face  to  spall. 

The  thickness  of  ashlar  joints  varies  from  ^  to  \  inch.  A  ^-inch 
joint,  when  pointed,  makes  very  good-looking  work.  A  ^-inch  joint 
is  too  wide  for  anything  but  rock-face  ashlar,  and  nothing  over  a 
^-inch  joint  should  be  used  for  heavy  work. 

205.  Backing. — Both  stone  and  brick  are  used  for  the  backing  of 
ashlar.  Brick  is  more  largely  used  for  this  purpose  than  stone, 

because  in  most  cases  it  is 
the  cheapest,  and  it  pos- 
sesses the  further  advan- 
tage that  the  plaster  may  in 
dry  climates  be  applied 
directly  to  the  brick,  while 
the  stone  backing  generally 
has  to  be  plugged  and 
stripped  for  lathing.  If 
brick  is  used  for  backing 
the  joints  should  be  made 
as  thin  as  possible,  and  it  is 
desirable  to  use  some 
cement  in  the  mortar  to 
prevent  shrinkage  in  the 
joints.  The  backing,  if  of 
brick,  should  never  be  less 
than  8  inches  in  thickness. 
If  a  hard  laminated  stone, 
with  perfectly  flat  and  par- 
allel beds,  can  be  obtained 
for  backing,  it  makes  a 
stronger  job  than  brick,  but  irregular  rubble  blocks  are  not  suitable 
for  anything  but  dwelling  house  walls,  unless  the  walls  are  made  one- 
fourth  thicker  than  with  brick  backing.  The  backing,  whether  of 
brick  or  stone,  should  be  carried  up  at  the  same  time  with  the  ashlar, 
and,  if  of  stone,  should  be  built  in  courses  of  the  same  thickness  as 
the  ashlar,  as  shown  in  J3,  Fig.  117. 

Bonding. — Ashlar  not  exceeding  12  inches  in  height  is  usually 
bonded  sufficiently  to  the  backing  by  making  the  stones  of  different 
thicknesses,  as  in  Fig.  117,  and  by  having  one  through  stone  to  every 
jo  square  feet  of  wall. 


Fig.  117. 


i8o  BUILDING  CONSTRUCTION. 

Where  the  ashlar  is  only  about  2  inches  or  4  inches  thick,  as  is 
generally  the  case  with  marble,  and  often  with  sandstones,  each  piece 
of  ashlar  should  be  tied  to  the  backing  by  an  iron  clamp,  about  \  of 
an  inch  thick  and  i  or  i£  inches  wide,  with  the  ends  turned  at  right 
angles,  as  shown  in  Fig.  114.  The  anchors  should  be  made  of  just 
the  right  length  for  the  longer  end  to  turn  up  just  on  the  inside  of 
the  wall.  Every  stone  should  have  one  clamp,  and  if  over  3  feet 
long  two  clamps  should  be  used.  There  should  also  be  belt  courses 
about  every  6  feet,  extending  8  inches  or  more  into  the  wall,  to  give 
support  to  the  ashlar. 

The  effective  thickness  of  a  wall  faced  with  thin  ashlar  is  only 
equal  to  the  thickness  of  the  backing.  When  iron  clamps  are  used 
for  tying  the  ashlar  they  should  be  either  galvanized  or  dipped  into 
hot  tar  to  prevent  being  destroyed  by  rust. 

2o6.  Slip   Joints. — Where  two  walls  differing  considerably  in 
height  come  together,  as  for  instance  where  the  front  or  side  wall  of 
a  church  joins  the  tower,  the  two  walls  should 
_l_     :    not  be  bonded  together,  but  the  low  wall  should 


TOWER.  be  "  housed  "  into  the  other,  so  as  to  form  a  con- 
tinuous vertical  joint  from  bottom  to  top,  as 
shown  in  Fig.  118. 

Such  a  joint  is  called  a  slip  joint.     All  mason 
work   built  with    lime  mortar  will  settle  some- 
Fig  ixg  what,  owing  to  a  slight  compression  in  the  joints, 

and  this  settlement  is  sometimes  sufficient  to 
cause  a  crack  where  a  high  and  low  wall  are  bonded  together.  In 
such  cases  there  is  also  a  chance  for  uneven  settlement  in  the  foun- 
dations,'even  when  carefully  proportioned.  With  a  slip  joint  a  mod- 
erate settlement  may  take  place  without  showing  on  the  outside. 

207.  Bond  Stones  and  Templates. — The  building  regula- 
tions of  certain  cities  require  that  bond  stones  shall  be  used  in  brick 
piers  of  less  than  a  certain  size.  When  such  stones  are  used  they 
should  be  of  some  strong  variety,  and  should  be  cut  the  full  size  of 
the  pier.  It  is  also  very  important  that  the  outside  and  inside  bricks 
be  brought  exactly  to  the  same  level  to  receive  the  stone,  for  if  the 
stone  bears  only  on  the  outside  bricks  the  weight  will  cause  them  to 
buckle  and  separate  from  the  pier,  while  if  the  weight  is  borne  by 
the  centre  of  the  pier  it  is  liable  to  crack  through  the  middle. 

Bond  stones  should  not  be  used  in  a  wall  in  the  manner  shown  in 
Fig.  119,  as  they  give  the  pressure  no  chance  to  spread,  but  keep  con- 


CUT  STONEWORK. 


181 


centrating  it  back  on  the  part  of  the  wall  immediately  under  the  bond 
stones,  as  shown  by  the  short  vertical  lines. 

Bearing  stones  used  under  the  ends  of  beams  or  girders  to  distrib- 
ute the  weight  on  the  walls  are  called  templates.  They  should  always 
be  of  a  very  hard,  strong  stone,  laminated  if  it  can  be  obtained,  and 
the  thickness  of  the  stone  should  be  one-third  of  the  narrowest 
dimension  of  the  stone,  unless  the  stone  is  unnecessarily  large,  but  in 
no  case  less  than  4  inches.  It  is  always  better  that  templates  be  too 
large  rather  than  too  small. 

The  area  of  the  templates  should  be  such  that  the  pressure  which 
it  transmits  to  the  wall  below  shall  not  exceed  120  pounds  per  square 
inch  for  common  brickwork,  or  150  pounds 
for  common  rubble  with  flat  beds. 

It  is  also  a  good  idea  to  place  a  flat  stone 
above  the  end  of  a  wooden  girder,  so  that 
the  wall  will  not  rest  on  the  wood,  which  is 
quite  sure  to  shrink  and  possibly  affect  the 
wall. 

208.  Setting  Stonework. — All  stones 
should  be  set  in  a  full  bed  of  mortar,  and 
any  stone  too  large  to  be  easily  lifted  by 
one  man  should  be  set  with  a  derrick. 

In  some  localities  slips  of  wood  are  pre- 
pared of  the  thickness  desired  for  the  joints 

and  laid  on  the  top  of  the  stone  below,  so  that  when  the  stone  is  set 
the  mortar  squeezes  out  until  the  stone  rests  on  the  slips  of  wood. 
After  the  mortar  has  set  or  hardened  the  slips  are  withdrawn.  The 
bed  of  mortar  should  always  be  kept  back  an  inch  or  more  from  the 
•edge  of  the  stone.  This  will  prevent  the  stone  bearing  just  on  the 
outer  edge,  and  save  raking  out  the  mortar  preparatory  to  pointing. 
In  damp  places  stonework  should  be  set  in  cement,  or  lime  and 
cement  mortar  ;  in  dry  situations  it  may  be  set  in  lime  mortar. 

Most  of  the  granular  limestones  and  marbles,  and  some  sandstones, 
are  stained  by  either  Portland  or  Rosendale  cement,  and  when  using 
any  of  these  stones  for  the  first  time  the  architect  should  ascertain 
their  liability  to  stain.  The  mortar  for  bedding  the  stone  can  always 
be  kept  from  the  face  of  the  stone  by  exercising  a  little  care,  and  the 
joints  afterward  pointed  with  some  material  that  does  not  stain. 
Stone  masons  are  often  very  careless  in  setting  stonework,  and  do  not 
bed  the  stones  evenly,  so  that  when  the  weight  comes  upon  them 
they  crack. 


Fig.  119. 


1 82 


BUILDING  CONSTRUCTION. 


Marble  and  limestone  are  sometimes  set  in  a  cement  made  of  lime, 
plaster  of  Paris  and  marble  dust,  and  called  Lafarge  cement.  WThen 
such  cement  is  used  for  setting,  and  other  cements  for  the  backing, 
the  back  of  the  stone  ashlar  should  be  plastered  with  the  former 
cement.  Window  and  door  sills  should  only  be  bedded  at  their  ends 
when  set  and  no  mortar  put  under  the  middle  of  the  sill,  otherwise 
the  settlement  of  the  walls  will  break  the  sill. 

Protecting. — The  carpenter's  specifications  should  contain  a 
clause  providing  for  the  boxing  of  all  mouldings,  sills  and  ornamental 
work  with  rough  pine  to  prevent  the  stone  being  damaged  during  the 
construction  of  the  building.  It  is  said  that  hem- 
lock stains  the  stone,  and  should  therefore  never 
be  used  for  this  purpose. 

209.  Pointing. — As  the  mortar  in  the  ex- 
posed edges  of  the  joints  is  especially  subject  to 
dislodgment  through  the  expansion  and  con- 
traction of  the  masonry  and  the  effects  of  the 
weather,  it  is  customary  after  the  masonry  is  laid 
to  refill  the  joints  to  the  depth  of  half  an  inch  or 
more  with  mortar  prepared 
especially  for  this  purpose. 
This  operation  is  called 
I  pointing. 
'  Pointing  is  generally  done 

as  soon  as  the  outside  of  ( 
a  the  building  is  completed, 
l  unless  it  should  be  too  late 
in  the  season,  when  it 
should  be  delayed  until 
spring.  Pointing  should  never  under  any  circumstances  be  done  in 
freezing  weather.  It  is  also  not  desirable  to  do  it  in  extremely  hot 
weather,  as  the  mortar  dries  too  quickly. 

Portland  cement  mixed  with  not  more  than  an  equal  volume  of 
fine  sand  and  such  coloring  matter  as  may  be  required,  with  just 
enough  water  to  give  the  compound  a  mealy  consistency,  makes  the 
most  durable  mortar  for  pointing.  If  the  stone  is  stained  by  cement,. 
Lafarge  cement  should  be  used,  or  a  putty  made  of  lime,  plaster  of 
Paris  and  white  lead. 

Before  applying  the  pointing  the  joint  should  be  raked  out  to  ther 
depth  of  an  inch,  brushed  clean  and  well  moistened. 


Fig.  120. 


Fig.  121. 


CUT  STONEWORK.  183 

The  mortar  is  applied  with  a  small  trowel  made  for  the  purpose 
and  then  squeezed  in  and  rubbed  smooth  with  a  tool  called  a  jointer 
(Fig.  120)  and  made  for  that  purpose.  Jointers  are  made  with  both 
hollow  and  concave  edges,  so  as  to  give  a  raised  or  concave  joint,  as 
shown  in  Fig.  121.  The  concave  joint  is  the  most  durable,  although 
the  raised  joint  makes  perhaps  the  handsomest  work. 

Cleaning  Down. — This  consists  in  washing  and  scrubbing  the 
stonework  with  muriatic  acid  and  water.  Wire  brushes  are  generally 
used  for  marble  work  and  sometimes  for  sandstone,  but  stiff  bristle 
brushes  usually  answer  the  purpose  as  well.  The  stones  should  be 
scrubbed  until  all  mortar  stains  and  dirt  are  entirely  removed.  The 
cleaning  down  is  done  in  connection  with  the  pointing. 

For  cleaning  an  old  front  the  sand  blast,  using  either  steam  or 
compressed  air,  does  the  work  most  effectively,  as  it  removes  from 
•fa  to  -^  of  an  inch  from  the  surface  of  the  stone,  making  it  look  like 
new.  Even  carving  can  be  successively  treated  in  this  way. 

210.  Strength  of  Stone  Masonry. — Practically  the  only  cases 
in  which  the  strength  of  stonework  need  be  considered  by  the  archi- 
tect, other  than  to  see  that  proper  construction  is  provided,  are  : 
a,  the  strength  of  piers  ;  b,  strength  of  columns  ;  c,  strength  of  lintels. 

Strength  of  Stone  Piers. — The  following  figures  may  be  taken  for 
the  working  strength  of  stone  piers.  The  figures  in  the  first  column 
may  be  taken  for  a  fair  quality  of  work  laid  in  good  lime  mortar, 
those  in  the  second  column  for  the  best  class  of  work  laid  in  cement: 

Concrete 5  to  20  tons. 

Rubble 5  to  15     " 

Squared  stone,  ^-inch  joints 15  to  20     " 

Sandstone  ashlar,  ^-inch  joints 10  to  20     " 

Limestone  ashlar,  |-inch  joints 20  to  25     " 

Granite  ashlar,  ^-inch  joints 30     " 

The  ashlar  to  be  at  least  as  thick  as  it  is  high  and  well  bonded. 

Strength  of  Columns. — A  stone  column,  free  from  defects,  carefully 
bedded  and  not  exceeding  ten  diameters  in  height,  should  safely 
carry  a  load  equal  to  one-fifteenth  of  the  breaking  load  of  stone  of 
the  same  kind  and  quality.  Any  column  loaded  with  over  fifteen 
tons  to  the  square  foot  should  be  bedded  in  Portland  cement  mortar, 
of  not  more  than  i  to  i,  and  the  mortar  should  not  be  allowed  to 
come  within  i  inch  of  the  edge  of  the  column  until  after  the  build- 
ing is  done,  when  the  joint  may  be  pointed  the  same  as  ashlar.  As  it 
is  difficult  to  secure  a  joint  which  will  stand  more  than  forty  tons  to 
the  square  foot,  that  should  be  the  limit  of  load  for  a  stone  column, 


i84  BUILDING  CONSTRUCTION. 

no  matter  how  strong  the  stone  is,  unless  extra  precautions  are  taken 
with  the  joints.  The  following  values  may  be  used  for  the  safe  loads 
of  columns  of  the  different  stones  specified,  the  shaft  of  the  column 
being  in  one  piece  : 

Longmeadow  (Mass.)  red  sandstone,  best 35  tons  per  square  foot. 

Potsdam  red  sandstone 40 

Manitou  (Colo.)  red  sandstone,  best 25  to  30 

Ohio  sandstone 25 

Fond  du  Lac  (Wis.)  sandstone 25 

Limestone,  Glens  Falls,  N.  Y 35 

Limestone,  Indiana 25  to  35 

Limestone,  strongest  varieties 40 

Marble,  Lee,  Mass 40 

Marble,  Rutland,  Vt 3°  to  35         " 

Granite,  any,  of  good  quality 40 

If  the  columns  are  built  up  of  several  pieces  the  joints  should  not 
exceed  -fa  of  an  inch  in  thickness,  and  the  bed  surfaces  should  be 
perfectly  true  and  square  to  the  axis  of  the  column. 

211.  Strength  of  Lintels. — A  lintel  is  nothing  more  than  a  stone 
beam,  and  the  same  formulae  apply  to  stone  as  to  wood,  with  the 
exception  of  the  quantity  representing  the  strength  or  "  modulus  of 
rupture  "  of  the  material.  The  following  formulae  give  the  strength 
of  lintels  under  distributed  and  concentrated  loads,  the  only  cases 
likely  to  occur  in  practice  : 

Distributed  breaking  load  =  «  X  breadth  X  square  of  depth  x  ^ 

span  in  feet 

Concentrated  centre  breaking  load  =  one-half  the  distributed  load. 

The  breadth  and  depth  should  be  taken  in  inches.  C  is  one- 
eighteenth  of  the  average  modulus  of  rupture,  and  may  be  taken  as 
follows : 

Granite,  100  ;  marble,  120;  limestone,  83;  sandstone,  70;  slate, 
300  ;  bluestone  flagging,  150. 

These  formulae  give  the  breaking  strength  of  the  lintel.  If  the  load 
on  the  lintel  consists  only  of  masonry,  and  is  not  subject  to  shocks  or 
impact  of  any  kind,  the  safe  load  may  be  taken  at  one-sixth  of  the 
breaking  load.  If  there  are  any  unfavorable  circumstances  the  safe 
load  should  not  exceed  one-tenth  of  the  breaking  load. 

Nearly  all  laminated  stones  are  stronger,  as  beams,  when  set  on 
edge,  and  where  the  full  strength  of  the  stone  is  required,  they  may 
with  advantage  be  set  in  this  way  and  be  protected  from  the  weather 
by  placing  a  moulded  course  above  set  on  its  natural  bed. 


CUT  STONEWORK.  185 

Floor  beams,  or  any  construction  carrying  a  live  or  moving  load, 
should  never  be  supported  on  a  stone  lintel.  The  above  formulas 
apply  to  a  slab  as  well  as  to  a  lintel,  although  if  the  slab  has  a  bear- 
ing on  all  four  sides  the  strength  will  be  considerably  increased. 

Example. — What  is  the  safe  distributed  load  of  a  granite  lintel,  6 
feet  opening,  20  inches  high  and  8  inches  thick  ? 

Answer. — Breaking  strength  —  2- -  X  100  =106,666  pounds. 

6 

One-sixth  of  this  gives  17,777  pounds  for  the  safe  distributed  load. 
Example  II. — What  is  the  safe  distributed  load  for  a  bluestone 
flag  4  feet  clear  span,  4  feet  wide  and  4  inches  thick  ? 

Answer.— Breaking  load  =  2><48X42Xi5o=  ^^  pounds. 

4 

As  the  load  on  a  flag  would  very  probably  be  a  live  or  moving 
load,  we  will  make  the  safe  load  only  one-tenth  of  the  breaking  load, 
or  5,760  pounds. 

212.  Measurement  of  Stonework. — Rough  stone  from  the 
quarry  is  usually  sold  under  two  classifications,  rubble  and  dimension 
stone.  Rubble  includes  the  pieces  of  irregular  size  most  easily 
obtained  from  the  quarry,  and  suitable  for  cutting  into  ashlar  12 
inches  or  less  in  height  and  about  2  feet  long.  Stone  ordered  of  a 
certain  size,  or  to  square  over  24  inches  each  way,  and  of  a  particular 
thickness,  is  called  dimension  stone.  The  price  of  the  latter  varies 
from  two  to  four  times  the  price  of  rubble. 

Rubble  is  generally  sold  by  the  perch  or  car  load.  Footings  and 
flagging  are  usually  sold  by  the  square  foot ;  dimension  stone  by  the 
cubic  foot.  In  Boston  granite  blocks  for  foundations  are  usually 
sold  by  the  ton,  and  rubble  for  foundations  is  often  sold  that  way  in 
various  localities. 

In  estimating  on  the  cost  of  stonework  put  into  the  building,  the 
custom  varies  with  different  localities,  and  even  among  contractors 
in  the  same  city. 

Dimension  stone  footings  (that  is  square  stone  2  feet  or  more  in 
width)  are  usually  measured  by  the  square  foot.  If  built  of  large 
rubble  or  irregular  stones  the  footings  are  measured  in  with  the  wall, 
allowance  being  made  for  the  projections  of  the  footings. 

Rubble  work  is  most  often  measured  by  the  perch,  which  consists  of 
24!  cubic  feet  in  the  East  and  of  i6f  cubic  feet  (by  custom)  in  Col- 
orado, and  in  some  localities  22  cubic  feet  are  called  a  perch. 

If  work  is  let  by  the  perch  it  should  be  distinctly  stated  in  the  con- 
tract the  number  of  cubic  feet  that  are  to  constitute  a  perch,  as  the 


1 86  BUILDING  CONSTRUCTION. 

custom  of  the  place  would  probably  prevail  in  a  dispute.  It  should 
also  be  stated  whether  or  not  openings  are  to  be  deducted  ;  as  a  rule 
rubble  walls  are  figured  solid,  unless  the  opening  exceeds  70  square 
feet. 

Occasionally  rubble  is  measured  by  the  cubic  yard,  or  27  cubic 
feet,  and  by  the  cord  of  128  cubic  feet. 

Stone  backing  is  generally  figured  the  same  as  rubble. 

Ashlar  is  almost  invariably  measured  by  the  square  foot,  the  price 
varying  with  the  kind  of  work  and  size  of  stones.  Openings  are 
generally  deducted,  but  width  of  jambs  measured  in  with  the  face 
work.  This  custom  varies,  however,  with  different  localities  and  kind 
of  work.  In  common  rock-face  ashlar  the  wall  is  often  figured  solid 
unless  the  openings  are  of  unusual  size. 

Flagging  and  slabs  of  all  kinds  are  always  figured  by  the  square  foot. 

Mouldings,  belt  courses  and  cornices  are  usually  figured  by  the 
lineal  foot,  irregular  shaped  pieces  by  the  cubic  foot.  All  carving  is 
figured  by  the  piece.  Some  contractors  figure  all  kinds  of  trimmings 
by  the  cubic  foot,  varying  the  price  according  to  the  amount  of  labor 
;nvolved.  Others  figure  the  cubic  feet  in  all  the  stone  to  get  the  value 
of  the  rough  stone,  and  then  figure  the  labor  separately — so  much  per 
lineal  foot  for  mouldings,  so  much  for  columns,  and  a  separate  figure 
for  carving.  This  is  the  most  accurate  method,  and  is  usually 
employed  by  contractors  for  granite  work.  Of  course  considerable 
experience  is  necessary  to  know  how  much  to  allow  for  labor  ;  the 
value  of  the  stone  itself  can  be  very  easily  computed. 

213.  Superintendence  of  Cut  Stonework. — As  with  all  other 
building  operations,  the  superintendent  needs  to  be  very  watchful  in 
inspecting  the  cut  stonework  and  its  setting,  to  prevent  defects  and 
imperfect  work  being  imposed  upon  him.  When  a  stone  is  once  built 
into  a  wall  it  can  only  be  removed  at  considerable  expense  and  delay 
and  much  vexation,  and  it  is  therefore  important  that  all  defects  be 
discovered  before  the  stone  is  set.  The  superintendent  must  also  be 
well  posted  on  the  various  ways  in  which  defects  are  covered  up,  so 
that  he  may  discover  them,  if  any  exist,  and  have  sufficient  firmness 
to  demand  that  all  unsound  or  defective  stones  shall  be  replaced  by 
sound  ones,  and  that  the  work  shall  be  done  in  the  manner  directed 
by  the  architect. 

Defects. — The  following  are  the  defects  most  likely  to  occur  in 
cut  stonework. 

Good  granges  are  liable  to  contain  local  defects,  such  as  seams, 
black  or  white  lumps  called  "knots,"  and  also  brown  stains  known 


CUT  STONEWORK.  187 

as  sap.  Any  of  these  defects  should  cause  the  stone  to  be  rejected. 
Seams  may  be  detected  by  striking  the  stone  with  a  hammer,  and 
those  which  do  not  ring  clearly  should  be  rejected. 

In  sandstones  the  most  common  defects  are  "  sand  holes  "  (which 
are  small  holes  filled  with  sand,  but  without  any  cementing  material, 
so  that  the  sand  soon  washes  out)  and  uneven  color.  Stones  from 
the  same  quarry  often  vary  considerably  in  color,  and  the  superin- 
tendent must  see  that  the  color  of  the  stone  is  uniform  throughout. 

Patching. — Often  in  cutting  stone  a  small  piece  will  get  broken 
from  a  large  stone,  and  the  contractor,  rather  than  throw  the  stone 
away,  will  either  stick  the  piece  on  again  or  cut  out  the  fractured 
part  and  fit  in  a  new  piece.  The  pieces  are  glued  on  with  melted 
shellac  and  then  rubbed  with  stone  dust  until  they  cannot  be  noticed 
by  a  casual  glance,  and  the  superintendent  must  look  sharply  at  the 
stones  to  be  sure  that  they  have  not  been  patched  in  this  way. 

At  first  these  patches  are  hardly  noticeable  and  do  no  harm,  but 
when  the  stone  gets  wet  the  patch  becomes  conspicuous,  and  in  time 
the  shellac  in  the  joint  is  washed  away  and  the  patch  drops  off. 

When  the  damaged  stone  is  large,  and  cannot  be  replaced  except 
at  great  expense  and  considerable  delay,  the  superintendent  might 
consent  to  have  it  patched,  but  he  should  see  that  it  is  done  right, 
and,  where  possible,  a  square  hole  should  be  cut  in  the  stone  and  a 
corresponding  piece  tightly  fitted  in,  and  then  cut  to  fit  the  stone  or 
moulding.  If  on  the  corner  of  a  stone  the  piece  can  generally  be 
dovetailed,  so  that  it  will  stay  in  place  without  the  aid  of  shellac. 
If  any  patched  stones  are  put  into  the  building  the  superintendent 
should  know  of  it  beforehand,  and,  as  a  rule,  it  will  be  wise  to  consult 
the  owner  of  the  building  about  it  before  the  stone  is  set. 

In  the  cutting  of  the  stone  the  most  common  fault  to  be  found  is  poor 
workmanship  or  too  coarse  a  surface.  Naturally  the  finer  a  surface  is 
tooled  or  crandalled  the  greater  the  expense,  hence  contractors  will 
generally  finish  the  stone  as  coarse  as  they  think  the  superintendent 
will  pass.  Very  often,  also,  sufficient  care  is  not  taken  in  matching  the 
ends  of  moulded  belt  courses,  cornices,  etc.  The  superintendent 
should  insist  that  all  the  pieces  are  cut  exactly  to  the  same  pattern, 
and  that  all  edges  are  true  and  free  from  nicks. 

It  is  a  very  common  occurrence  to  find  some  window  sills  that  are 
not  of  sufficient  width  to  be  well  covered  by  the  wood  sill.  The  back 
of  the  stone  sills  should  extend  at  least  \\  inches  beyond  the  face  of 
the  wood  sill,  and  the  back  of  the  wash  should  be  cut  to  a  straight 
line,  without  any  holes  or  scant  surfaces. 


i88  BUILDING  CONSTRUCTION. 

The  ashlar,  especially  when  rock-face,  is  apt  to  be  too  thin  in 
places,  and  to  have  very  poor  bed  joints.  The  superintendent  should 
insist  that  the  bed  joints,  top  and  bottom,  be  at  least  3  inches  wide 
at  the  thinnest  part,  and  that  they  be  cut  square  to  the  face  of  the 
work.  He  should  also  examine  the  stones  to  see  that  they  have  been 
cut  so  as  to  lay  on  their  natural  beds.  The  proper  bonding  and 
anchoring  of  the  ashlar  and  trimmings  should  also  receive  careful 
attention.  The  anchoring  of  gable  copings  should  be  especially 
looked  after,  as  it  is  not  infrequent  that  such  copings  slide  out  of 
place  and  fall  to  the  ground  from  neglect  in  this  particular.  One 
would  naturally  suppose  that  the  builder  himself  would  see  that  his 
work  was  done  securely,  if  not  handsomely  ;  but  it  seems  to  be  a  gen- 
eral fault  amongst  builders  to  trust  a  good  deal  to  luck,  and  to  use  as 
few  precautions  to  insure  it  as  possible.  In  these  days,  when  every- 
thing is  done  with  a  rush,  there  are  also  many  builders  that  are  igno- 
rant of  the  best  methods  of  doing  work,  or  that  consider  them  unnec- 
essary and  not  "  practical." 

When  finials  or  similar  stones  are  cut  in  two  pieces  they  should  be 
secured  together  by  iron  dowels  set  in  almost  clear  Portland  cement. 
The  superintendent  should  constantly  bear  in  mind  that  stonework 
cannot  be  too  well  anchored  and  bonded. 

The  superintendent  should  also  caution  the  foreman,  when  setting 
arches,  columns,  etc.,  not  to  let  the  mortar  come  within  f  of  an  inch 
of  the  face  of  the  stone.  Moulded  arches,  particularly,  need  to  be 
set  with  great  care,  as  if  the  mortar  comes  out  to  the  face  the  joint 
may  be  a  little  full  at  the  edge  and  cause  the  moulding  to  "  sliver  " 
or  "spall"  at  the  joints.  It  is  not  uncommon  to  see  arch  stones 
and  columns  cracked  on  account  of  neglect  of  this  precaution. 

When  the  pointing  is  being  done  the  superintendent  must  carefully 
watch  the  operation  of  raking  out  the  joints  to  receive  the  pointing. 
The  old  mortar  should  be  raked  out  to  the  depth  of  at  least  J  of  an 
inch.  If  the  work  is  not  watched,  however,  it  may  be  found  in  a 
year  or  two  that  the  raking  of  the  joints  was  only  partially  done,  if 
not  neglected  altogether,  and  that  the  pointing  mortar  was  only  stuck 
on  to  the  face  of  the  joint. 

There  will  naturally  be  many  other  points  in  connection  with  the 
stonework  that  will  require  careful  supervision  to  secure  a  good  and 
durable  job,  but  careful  attention  to  those  above  noted  will  lead  to  a 
pretty  thorough  inspection  of  the  whole  work. 


CHAPTER  VII. 
BRICKWORK. 


BRICKS. 

214.  Bricks   are   more   extensively   used  in  the  construction   of 
buildings  than  any  other  material  except  wood.     At  the  present  time 
briok  and  terra  cotta  architecture  is  decidedly  in  the  ascendency, 
and  a  great  deal  of  capital  is  invested  in  the  manufacture  of  bricks 
of  all  kinds,  shapes  and  colors. 

Good  bricks  possess  the  advantage  over  stone  of  being  practically 
indestructible,  either  from  the  action  of  the  weather,  the  acids  of  the 
atmosphere  or  fire  ;  they  may  be  had  in  almost  any  desirable  shape, 
size  or  color,  and  are  more  easily  handled  and  built  into  a  wall  than 
stone.  Brickwork  is  also  much  cheaper  than  cut  stonework,  and  in 
most  localities  is  less  expensive  than  common  rubble.  Unfortu- 
nately, however,  all  bricks  cannot  be  classed  under  the  above  heading, 
as  there  are  many  that  are  soft  and  porous,  and  are  far  from  durable 
when  exposed  to  dampness.  Except  in  very  dry  soils  bricks  are  not 
as  well  adapted  for  foundations  as  stonework,  nor  can  they  be  used 
for  piers  and  columns  that  support  very  heavy  loads. 

As  there  are  many  different  kinds  and  qualities  of  bricks,  as  well 
as  good  and  bad  methods  of  using  them,  the  architect  must  know 
something  about  the  manufacture  of  bricks,  their  characteristics  and 
the  best  methods  of  using  them  to  properly  prepare  his  designs  and 
specifications  and  to  superintend  the  construction. 

215.  Composition  of  Bricks.— Ordinary  building  bricks  are 
made  of  a  mixture  of  clay  and  sand  (to  which  coal  and  other  foreign 
substances  are  sometimes  added),  which  is  subjected  to  various  pro- 
cesses, differing  according  to  the  nature  of  the  material,  the  method 
of  manufacture  and  the  character  of  the  finished  product. 

After  being  properly  prepared  the  clay  is  formed  in  moulds  to  the 
desired  shape,  then  dried  and  burnt. 

The  Clay. — The  quality  of  a  brick  depends  principally  upon  the 
kind  of  clay  used.  The  material  generally  employed  for  making 
common  bricks  consists  of  a  sandy  clay,  or  silicate  of  alumina,  usu- 
ally containing  small  quantities  of  lime  magnesia  and  iron  oxide.  If 


I9o  BUILDING  CONSTRUCTION. 

the  clay  consists  almost  entirely  of  alumina  it  will  be  very  plastic, 
but  will  shrink  and  crack  in  drying,  warp  and  become  very  hard 
under  the  influence  of  heat 

Silica,  when  added  to  pure  clay  in  the  form  of  sand,  prevents 
cracking,  shrinking  and  warping,  and  allows  a  partial  vitrification  of 
the  materials.  The  larger  the  proportion  of  sand  present  the  more 
shapely  and  uniform  in  texture  will  be  the  bricks.  An  excess  of  sand, 
however,  renders  the  bricks  too  brittle  and  destroys  cohesion. 
Twenty-five  per  cent,  of  silica  is  said  to  be  a  good  proportion. 

The  presence  of  oxide  of  iron  in  the  clay  renders  the  silica  and 
alumina  fusible  and  adds  greatly  to  the  hardness  and  strength  of  the 
bricks.  Iron  also  has  a  great  influence  upon  the  color  of  the  bricks 
(see  Section  229),  the  red  color  being  due  to  the  presence  of  iron.  A 
clay  which  burns  to  a  red  color  will  make  a  stronger  brick,  as  a  rule, 
than  one  whose  natural  color  when  burnt  is  white  or  yellow. 

"  Lime  has  a  twofold  effect  upon  the  clay  containing  it.  It  dimin- 
ishes the  contraction  of  the  raw  bricks  in  drying,  and  it  acts  as  a  flux 
in  burning,  causing  the  grains  of  silica  to  melt,  and  thus  binding  the 
particles  of  the  bricks  together.  An  excess  of  lime  causes  the  bricks 
to  melt  and  lose  their  shape.  Again,  whatever  lime  is  present  must 
be  in  a  very  divided  state.  Lumps  of  limestone  are  fatal  to  a  clay 
for  brickmaking.  When  a  brick  containing  a  lump  of  limestone  is 
burnt  the  carbonic  acid  is  driven  off,  the  lump  is  formed  into  '  quick- 
lime '  and  is  liable  to  slake  directly  the  brick  is  wetted  or  exposed  to 
.the  weather.  Pieces  of  quicklime  not  larger  than  pin  heads  have 
been  known  to  detach  portions  of  a  brick  and  to  split  it  to  pieces. 
'  The  presence  of  lime  may  be  detected  by  treating  the  clay  with  a 
little  dilute  sulphuric  acid.  If  there  is  lime  present  an  effervescence 
will  take  place." 

For  the  best  qualities  of  pressed  brick  the  clay  is  carefully  selected 
.both  for  chemical  composition  and  color,  and  very  often  two  or  three 
^qualities  of  clay  from  different  sources  are  mixed  together  to  obtain 
the  desired  composition. 

Clays  of  especially  fine  quality  are  often  mixed  and  shipped  to  dis- 
tant portions  of  the  country  the  same  as  other  raw  materials. 

2l6.  Manufacture.  —Handmade  Bricks. — Most  of  the  common 
bricks  used  in  this  country,  especially  in  the  smaller  towns  and  cities, 
are  still  made  by  hand.  The  process  consists  of  throwing  the  clay 
into  a  circular  pit,  where  it  is  mixed  with  water  and  tempered  with  a 
tempering  wheel  worked  by  horse  power,  until  it  becomes  soft  and 
plastic,  and  is  then  taken  out  and  pressed  into  the  moulds  by  hand. 


BRICKWORK.  191 

Unless  the  clay  already  contains  sufficient  sand,  additional  sand  is 
added  to  it  as  it  is  put  into  the  pit,  and  often  coal  dust  or  sawdust  is 
added  to  assist  the  burning.  In  some  localities  screened  cinders  are 
mixed  with  the  clay. 

In  moulding  brick  by  hand  the  mould  is  dipped  either  in  water  or 
fine  sand  to  prevent  the^bricks  from  adhering  to  the  mould.  If  dipped 
in  water  the  process  is  called  "slop  moulding,"  and  if  in  sand  the 
bricks  are  called  "sand  struck."  The  latter  method  gives  cleaner 
and  sharper  bricks  than  those  produced  by  "slop  moulding." 

After  being  shaped  in  the  mould  the  bricks  are  laid  in  the  sun,  or 
in  a  dry  house,  to  dry  for  three  or  four  days,  after  which  they  are 
stacked  in  kilns  and  fired. 

When  the  green  bricks  are  dried  in  the  open  air  they  occasionally 
get  caught  in  a  shower,  which  gives  them  a  pitted  effect,  that  is 
generally  considered  undesirable.  Unless  the  edges  are  much 
rounded,  however,  it  does  not  affect  the  strength  of  the  bricks,  and 
they  may  be  used  in  the  interior  of  the  wall. 

217.  Machine-made  Bricks. — Where  bricks  are  made  on  a  large 
scale  the  work  is  now  done  almost  entirely  by  machinery,  commenc- 
ing with  the  mining  of  the  clay  by  steam  shovels  and  ending  by  burn- 
ing in  patent  kilns. 

A  great  variety  of  machines  are  now  made  for  preparing  the  clay 
and  for  making  the  raw  bricks  ;  they  differ  more  or  less  widely  in 
construction  and  principle,  but  may  be  divided  into  three  classes, 
according  to  the  method  of  manufacture  for  which  they  are  adapted. 

There  are  practically  three  methods  employed  in  making  bricks, 
viz.:  The  soft  mud  process,  the  stiff  mud  process  and  the  dry  clay 
process,  and  the  machines  are  also  classed  under  one  of  these  head- 
ings. 

The  general  processes  employed  in  these  methods  are  as  follows  : 

Soft  Mud  Process. — This  is  essentially  the  same  process  as  that 
employed  when  the  bricks  are  made  by  hand.  When  machinery  is 
used  the  various  steps  are  about  as  follows  :  As  the  clay  is  brought 
from  the  bank  it  is  thrown  into  a  pit  (about  6  feet  deep  and  8x12 
feet  in  area)  lined  with  planks  ;  water  is  then  turned  into  the  pit  and 
the  clay  allowed  to  soak  for  twenty-four  hours.  Generally  three  pits 
are  provided,  so  that  the  clay  in  one  may  be  soaking  while  the  second 
is  being  emptied  and  the  third  filled.  If  coal  dust  is  to  be  mixed 
with  the  clay  it  is  thrown  into  the  pit  in  the  proper  proportion.  After 
spaking  twenty-four  hours  in  the  pit  the  clay  is  thrown  out  on  to  an 
endless  chain,  which  carries  it  along  to  the  machine,  into  which  it 


,92  BUILDING  CONSTRUCTION. 

falls.  The  upper  part  of  a  soft  clay  machine  contains  a  revolving 
shaft,  to  which  arms  are  affixed.  These  arms  break  up  and  thor- 
oughly work  the  soft  clay,  and  it  falls  to  the  bottom  of  the  machine, 
where  revolving  blades  force  it  forward,  and  a  plunger  working  up 
and  down  forces  the  clay  into  a  mould  placed  under  the  orifice.  The 
filled  mould  is  then  drawn  or  forced  out  on  to  a  shelf  or  table  and 
another  mould  placed  under  the  machine.  There  are  several  styles 
of  machines,  but  they  all  work  on  about  this  plan.  Sometimes  the 
clay  is  worked  in  a  pug  mill  before  being  thrown  into  the  machine. 

After  being  drawn  from  the  machine  the  filled  moulds  are  emptied 
by  hand  and  the  bricks  taken  to  the  dry  shed.  For  drying  soft  mud 
bricks  the  "  pallet  "  system  is  generally  employed.  The  "  pallets  " 
are  thin  boards  about  12x24  inches  in  size.  The  bricks  are  placed 
on  these,  and  then  the  pallets  are  placed  on  racks,  arranged  so  that 
the  air  may  have  free  access  to  the  bricks.  The  stacks  should  always 
be  protected  by  a  low  roof. 

2l8.  Stiff  Mud  Process. — The  essential  difference  between  this 
process  and  the  foregoing  is  that  in  the  stiff  mud  process  the  clay  is 
first  ground,  or  disintegrated,  and  only  enough  water  is  added  to 
make  a  stiff  mud.  The  mud,  after  being  pugged,  is  forced  through 
a  die  in  a  continuous  stream,  whose  section  is  the  size  of  a  brick,  and 
the  bricks  are  then  cut  off. 

The  process  varies  more  or  less  in  different  yards  and  with  dif- 
ferent clays,  but  when  most  thoroughly  carried  out  the  various 
steps  in  their  order  are  as  follows :  First,  the  mining  of  the 
clay  ;  second,  breaking  up  the  lumps  (generally  in  a  pug  mill)  ; 
third,  grinding  of  the  clay,  usually  in  a  dry  pan  (see  Section  221)  ; 
fourth,  tempering  the  clay,  either  in  a  separate  pug  mill  or  in  the 
machine,  and  fifth,  passing  the  clay  through  the  machine  and  cutting 
off  the  bricks. 

There  are  two  primary  types  of  stiff  mud  brick  machines,  viz.: 
The  auger  and  plunger  types.  Of  these  the  auger  machines  are  the 
most  numerous  and  generally  considered  the  most  satisfactory.  The 
auger  machine  consists  of  a  closed  tube  of  cylindrical  or  conical  shape, 
in  which,  on  the  line  of  the  axis  of  the  tube,  revolves  a  shaft,  to 
which  is  attached  the  auger  and  auger  knives.  The  knives  are  so 
arranged  as  to  cut  and  pug  the  clay  and  force  it  forward  into  the 
auger.  The  function  of  the  auger  is  to  compress  and  shape  the  clay 
and  force  it  through  the  die.  When  the  clay  passes  through  the  die 
it  is  compressed  to  as  great  an  extent  as  it  can  be  in  its  semi-plastic 
condition.  The  opening  in  the  die  is  made  the  size  either  of  the  end 


BRICKWORK.  193 

or  side  of  a  brick,  and  a  continuous  bar  of  clay  is  constantly  forced 
through  it  on  to  a  long  table.  Various  automatic  arrangements  are 
provided  for  cutting  up  this  bar  into  pieces  the  size  of  a  brick.  If 
the  section  of  the  bar  is  the  same  size  as  the  end  of  a  brick  the  bricks 
are  end  cut ;  if  the  section  of  the  bar  is  that  of  the  side  of  a  brick 
the  bricks  are  side  cut.  With  the  end-cut  brick  the  clay  may  issue 
from  the  machine  in  one,  two,  three  or  even  four  streams. 

From  the  cut-off  table  the  green  bricks  pass  to  the  off -bearing  belt, 
from  which  they  are  taken  to  the  represses  or  dryers. 

In  the  plunger  brick  machine  the  clay  is  forced  into  a  closed  box 
or  pressing  chamber,  in  which  a  piston  or  plunger  reciprocates  and 
forces  the  clay  through  the  die.  The  action  of  this  type  of  machine 
must  of  necessity  be  intermittent.  When  the  plunger  machine  is 
used  the  clay  is  generally  tempered  in  a  pug  mill  before  passing  to 
the  machine. 

219.  Comparison  of  Soft  Mud  and  Stiff  Mud  Bricks.— 
Soft  mud  bricks  are  made  under  little  or  no  pressure,  and  are,  there- 
fore, not  as  dense  as  the  stiff  mud  bricks.     It  is  claimed,  however,  that 
in  the  soft  mud  bricks  the  particles  adhere  more  closely,  and  that  when 
the  brick  are  properly  made  and  burned  they  are  the  most  durable  of 
all  bricks.     Soft  mud  bricks,  after  having  lain  in  a  foundation  on  the 
shore  of  a  river  for  fifty-four  years,  were  found  in  as  perfect  condi- 
tion as  when  laid.     Soft  mud  bricks  are  also  generally  more  perfect 
in.  shape  than  stiff  mud  bricks  and  better  adapted  for  painting. 

Stiff  mud  bricks,  owing  to  the  nature  of  the  clay  and  the  details  of 
manufacture,  often  contain  laminations,  or  planes  of  separation, 
which  more  or  less  weaken  the  bricks. 

Those  made  by  the  plunger  machine  also  sometimes  contain  voids 
caused  by  the  air  which  occasionally  passes  with  the  loose  clay  into 
the  pressure  chamber,  and,  being  unable  to  escape,  passes  out  with 
the  clay  stream  and  renders  it  more  or  less  imperfect. 

The  manufacture  of  stiff  mud  bricks,  however,  is  constantly 
increasing. 

In  some  localities  soft  mud  bricks  are  the  cheapest  ;  in  others  the 
stiff  mud  have  the  advantage.  The  difference  in  cost,  however",  is 
usually  very  slight. 

The  soft  mud  bricks  take  longer  to  dry,  but  are  more  easily  burnt. 

220.  Repressing. — Both  soft  and  stiff  mud  brick  are  often  repressed 
in  a  separate  machine.     Repressing  reshapes  the  brick,  rounds  the 
corners  if  desired,  trues  it   in    outline  and   makes   a   considerable 


I94  BUILDING  CONSTRUCTION. 

improvement  in  its  appearance.  A  properly  formed  stiff  mud  brick, 
however,  is  not  improved  in  structure  by  repressing. 

221.  Dry  Clay  Process. — This  process  is  especially  adapted  to 
clays  that  contain  only  about  7  per  cent,  of  moisture  as  they  come 
from  the  bank,  the  clay  being  apparently  perfectly  dry.  Wet  clays  are 
sometimes  dried  and  then  submitted  to  the  same  process,  but  the 
expense  of  drying  materially  increases  the  cost  of  manufacture. 

The  various  operations  generally  employed  in  making  brick  by  this 
process  may  be  briefly  described  as  follows  : 

The  first  step  is  the  mining  of  the  clay,  which  may  be  done  either 
by  hand  or  steam  shovel,  according  as  circumstances  may  direct. 
After  being  mined  the  clay  is  generally  stored  under  cover,  so  as 
always  to  have  a  supply  on  hand,  and  also  to  permit  of  further  dry- 
ing and  disintegrating.  Sometimes,  however,  the  clay  is  taken 
directly  from  the  bank  to  the  dry  pan. 

Probably  most  of  the  dry  press  brick  that  are  manufactured  are 
made  from  two  or  more  grades  of  clay,  which  are  mixed  in  propor- 
tions determined  by  trial  as  the  clay  is  thrown  into  the  dry  pan. 

From  the  dump  the  clay  is  thrown  into  a  dry  pan,  which  is  a  cir- 
cular machine  about  4  feet  in  diameter  and  2  feet  deep,  with  a  per- 
forated metal  bottom.  In  this  machine,  or  pan  as  it  is  called,  are 
two  wheels,  which  constantly  revolve  on  a  horizontal  axis  and  grind 
the  clay  between  them  and  the  bottom  of  the  pan,  the  pan  itself 
revolving  at  the  same  time.  The  clay  as  it  is  ground  passes  through 
the  holes  in  the  bottom  of  the  pan  and  falls  on  to  a  wide  belt,  which 
carries  it  above  an  inclined  screen,  on  to  which  it  falls.  Such  por- 
tions of  the  clay  as  are  sufficiently  finely  ground  fall  through  the 
screen  on  to  another  belt,  and  the  coarser  particles  roll  into  the  dry 
pan,  to  be  again  ground  and  carried  on  to  the  screen. 

The  belt  which  receives  the  fine  clay  from  the  screen  carries  it  to 
a  mixing  pan,  which  is  a  machine  contrived  to  thoroughly  mix  the 
particles  of  the  clay.  From  the  mixing  pan  the  clay  falls  into  the 
hopper  of  the  pressing  machine,  and  from  the  hopper  it  falls  into  the 
moulds,  where  it  is  subjected  to  great  pressure,  which  compresses  it 
to*  the  size  of  the  brick  and  then  pushes  the  pressed  brick  on  to  a 
table.  From  the  table  of  the  machine  the  bricks  are  taken  by  hand, 
placed  on  a  barrow,  or  car,  and  transferred  to  the  kiln. 

Different  manufacturers  may  vary  these  operations  somewhat,  but 
the  process,  and  also  the  machines,  are  essentially  like  the  above  in 
manufacturing  pressed  brick. 


BRICKWORK.  195 

The  pressing  machines  are  so  constructed  that  the  loose  clay  is 
made  to  evenly  fill  a  steel  box  of  the  width  and  length  of  the  intended 
brick,  but  much  deeper.  Into  these  boxes  a  plunger  is  forced,  whichi 
compresses  the  clay  until  the  desired  thickness  is  reached,  when  the1 
plunger  stops.  If  the  clay  falls  more  compactly  into  one  box,  or 
mould,  than  into  another,  the  brick  from  the  first  mould  will  be  the 
denser,  as  the  plunger  falls  just  so  far,  no  matter  how  much  clay  is  in 
the  mould. 

Moulded  bricks  are  made  in  exactly  the  same  way,  the  only  differ- 
ence being  that  the  box  is  made  to  give  the  shape  of  brick  desired. 

Most  of  the  pressed  brick  machines  admit  a  small  jet  of  steam  into 
the  clay  just  before  it  passes  into  the  moulds  to  slightly  moisten  it. 

Bricks  made  by  this  process  are  very  dense,  and  generally  show  a 
high  resistance  to  compression,  but  the  general  opinion  is  that  the 
particles  do  not  adhere  as  well  as  when  the  clay  is  tempered,  and 
that  dry  pressed  bricks  will  not  prove  as  ^enduring  as  soft  mud 
bricks,  although  the  former  are  now  most  extensively  used  for  face 
bricks. 

When  the  term  pressed  bricks  is  used  it  should  refer  to  bricks  made 
by  the  dry  process,  although  many  so-called  pressed  bricks,  or  face 
bricks,  are  made  by  repressing  soft  mud  bricks. 

222.  Drying  and  Burning. — Bricks  made  by  the  soft  mud  pro- 
cess always  have  to  be  dried  before  placing  in  the  kiln  ;  those  made 
by  the  stiff  mud  process  are  generally,  although  not  always,  stacked 
in  a  dry  house  from  twelve  to  twenty-four  hours.  The  drying  of  the 
bricks  is  an  important  process,  and  where  bricks  are  manufactured 
on  a  large  scale  the  drying  is  generally  accomplished  by  artificial 
means. 

After  being  sufficiently  dried  the  bricks  are  stacked  in  a  kiln  and 
burned. 

Three  styles  of  kilns  are  used  for  burning  bricks,  viz.:  Up-draft^ 
down-draft  and  continuous. 

Up-draft  Kiln. — This  is  the  style  of  kiln  that  was  almost  univer- 
sally used  in  this  country  for  burning  bricks  previous  to  1870,  and  is 
still  used  more  than  either  of  the  other  kilns,  especially  in  small  yards 
where  the  bricks  are  manufactured  by  hand. 

The  old-fashioned  up-draft  kiln  is  nothing  but  the  bricks  them-* 
selves  built  into  a  pile  about  20  to  30  feet  wide  and  30  to  40  feet 
long,  ar>d  perhaps  12  or  15  feet  high.  The  sides  and  ends  of  the 
piles  are  plastered  with  mud  to  keep  in  the  heat,  and  the  top  is  gen- 
erally covered  with  dirt  and  sometimes  protected  with  a  shed  roof 


I96  BUILDING  CONSTRUCTION. 

The  bricks  are  piled  in  such  a  way  as  to  form  a  row  of  arched 
openings  extending  entirely  across  the  kiln,  and  in  these  arches  the 
fire  is  built  The  dried  bricks  are  loosely  piled  above  these  arches, 
and  as  the  kiln  is  burnt  those  nearest  the  fire  are  so  intensely  heated 
as  to  become  vitrified,  while  those  at  the  top  of  the  kiln  are  but 
slightly  burned,  with  a  gradual  gradation  of  hardness  between  them. 
It  is  from  this  difference  in  the  burning  that  the  terms  "  arch  brick," 
"  red  brick  "  and  "  salmon  brick  "  originated.  As  there  is  nothing 
but  the  natural  tendency  of  heated  air  to  rise  to  produce  a  draft,  its 
direction  is  of  course  upward,  hence  the  name. 

The  modern  up-draft  kiln  has  permanent  sides  made  of  a  12  or 
1 6-inch  brick  wall  laid  in  mortar,  and  heat  is  generated  in  ovens  with 
iron  grates  built  outside  of  the  permanent  walls,  and  only  flames  and 
heat  enter  the  kiln  through  fire  passages  in  the  walls  connecting  the 
furnaces  with  the  kiln  proper.  The  top  of  the  kiln  is  also  paved 
with  smooth,  hard  bricks,  laid  so  as  to  form  a  close  cover  that  can 
be  opened  or  closed  as  desired.  The  bricks  are  piled  in  the  same 
way  as  described  above,  the  arches  being  left  opposite  the  furnaces. 
With  these  improvements  the  bricks  can  be  much  more  evenly 
burned  and  with  a  less  consumption  of  fuel.  The  burning  of  a  kiln 
of  brick  requires  about  a  week.  After  the  fires  have  been  burning  a 
sufficient  length  of  time  they  are  permitted  to  go  out,  and  all  the  out- 
side openings  tightly  closed  to  keep  out  the  cold  air,  and  thus  allow 
the  bricks  to  cool  gradually.  It  requires  much  skill  and  practice  to 
burn  a  kiln  of  bricks  successfully. 

223.  Doum-draft  Kilns. — Kilns  of  this  class  require  permanent 
walls  and  a  tight  roof.  The  floor  must  be  open  and  connected 
by  flues  with  a  chimney  or  stack.  These  kilns  are  more  often  made 
circular  in  plan  and  in  the  shape  of  a  beehive,  although  they  are  also 
made  of  a  rectangular  shape.  The  heat  is  generated  in  ovens  built 
outside  of  the  main  walls,  and  the  flames  and  gases  enter  the  kiln 
through  vertical  flues,  carried  to  about  half  the  height  of  the  kiln. 
The  heat,  therefore,  practically  enters  the  kiln  at  the  top  and  being 
drawn  downward  by  the  draft  produced  by  the  chimney,  passes 
through  the  pile  of  bricks  and  the  openings  in  the  floor  into  the  flues 
beneath,  and  hence  to  the  chimney  or  shaft.  It  is  claimed  that  all 
kinds  of  clay  wares  may  be  burnt  more  evenly  in  down-draft  kilns, 
and  terra  cotta  and  pottery  are  almost  always  burnt  in  such  kilns.  For 
terra  cotta  and  pottery  the  beehive  shape  is  generally  used,  several 
kilns  being  connected  with  one  stack. 


BRICKWORK.  197 

224.  Continuous  Kilns. — These  kilns  derive  their  name  from  the 
fact'that  the  heat  is  continuous  and  the  kilns  are  kept  continuously 
burning.     Continuous  kilns  are  very  different,  both  in  construction 
and  working,  from  the  other  two  styles,  and  are  also  very  expensive 
to  construct.    There  are  various  styles  of  continuous  kilns,  each  being 
protected  by  letters  patent. 

The  most  common  type  is  that  of  two  parallel  brick  tunnels 
connected  at  the  ends.  The  outer  walls  are  sometimes  8  feet 
thick  at  the  bottom  and  4  feet  thick  at  the  top.  Various  flues 
are  built  in  these  walls.  The  coal  in  continuous  kilns  is  put  in  from 
the  top.  The  bricks  are  piled  in  the  kilns  in  sections,  the  sections 
being  separated  by  paper  partitions,  and  each  section  is  provided 
with  about  four  openings  in  the  top  for  putting  in  the  coal.  After 
the  kiln  is  started  one  section  at  a  time  is  kept  burning,  and  the 
heated  gases  are  drawn  through  the  next  section  so  as  to  dry  the 
bricks  in  that  section  before  burning.  There  are  often  twenty  or 
more  sections  in  one  kiln,  and  while  one  section  is  being  burnt  and 
others  dried,  others  are  being  filled  and  others  are  cooling  or  being 
emptied. 

Continuous  kilns  require  a  powerful  draft  to  make  them  work  suc- 
cessfully ;  this  draft  is  generally  provided  by  a  tall  stack. 

The  principal  advantages  claimed  for  the  continuous  kiln  are  that 
it  takes  less  fuel  to  burn  the  bricks,  and  a  greater  percentage  of  No.  i 
bricks  are  obtained  than  in  other  kilns.  The  question  of  the  kind 
of  kiln  to  be  used,  however,  is  principally  one  of  economy  to  the 
manufacturer,  as  it  makes  no  particular  difference  to  the  architect  in 
what  kind  of  a  kiln  the  brick  are  burnt. 

225.  Glazed  and  Enameled  Brick. — These  terms  are  used  to 
designate  bricks  that  have  a  glazed  surface,  the  term  "  enameled  " 
being  applied  indiscriminately  to  all  bricks  having  such  a  surface. 

There  is.  however,  quite  a  difference  between  a  glazed  brick  and 
an  enameled  brick.  The  true  enamel  is  fused  into  the  clay  without 
an  intermediate  coating,  and  the  enamel  is  opaque  in  itself,  whereas 
a  glaze  is  produced  by  first  covering  the  clay  with  a  "slip"  and  then 
with  a  second  coat  of  transparent  glaze  resembling  glass. 

In  the  manufacture  of  glazed  bricks  the  unburnt  brick  is  first  coated 
on  the  side  which  is  to  be  glazed  with  a  thin  layer  of  "slip,"  which 
is  a  composition  of  ball  clay,  kaolin,  flint  and  feldspar.  The  slip 
adheres  to  and  covers  the  clay,  and  at  the  same  time  receives  and 
holds  the  glaze.  The  glaze  is  put  on  very  thin,  and  is  composed  of 
materials  which  fuse  at  about  the  temperature  required  to  melt  cast 


,98  BUILDING  CONSTRUCTION, 

iron,  and  leaves  a  transparent  body  covering  the  white  slip.  With  a 
glazed  brick  it  is  the  slip  that  gives  the  color  of  the  brick,  and  as  the 
slip  covers  the  brick,  the  latter  may  be  either  red  or  white.  Not  all 
bricks,  however,  are  suitable  for  glazing. 

Enameled  bricks  are  made  from  a  particular  quality  of  clay,  gen- 
erally containing  a  considerable  proportion  of  fire  clay.  The  enamel 
may  either  be  applied  to  the  unburnt  brick  or  to  the  brick  after  it  is 
burnt.  The  latter  method,  it  is  claimed,  produces  the  most  perfect 
brick. 

In  burning,  the  enamel  fuses  and  unites  with  the  body  of  the  brick, 
but  does  not  become  transparent,  and  therefore  shows  its  own  color. 

The  manufacture  of  a  true  enameled  brick  is  a  much  more  expen- 
sive operation  than  that  of  making  a  glazed  brick,  besides  being  a 
very  difficult  operation.  For  this  reason  the  glazed  process  is  the 
one  most  generally  employed,  both  in  this  country  and  in  England. 

It  is  claimed  that  an  enameled  brick  is  more  durable  than  a  glazed 
brick  and  will  not  so  readily  chip  or  peel.  The  enamel  is  also  the 
purest  white. 

An  enameled  surface  may  be  distinguished  from  one  that  is  sim- 
ply glazed  by  chipping  off  a  piece  of  the  brick.  The  glazed  brick 
will  show  the  layer  of  slip  between  the  brick  and  the  glaze,  while  an 
enameled  brick  will  show  no  line  of  demarkation  between  the  body 
of  the  brick  and  the  enamel. 

After  the  brick  are  in  the  wall  none  but  an  expert  can  distinguish 
betweeh  the  two.  Probably  most  of  the  so-called  enameled  bricks- 
that  have  been  used  in  this  country  are  really  glazed. 

The  bricks  are,  of  course,  enameled  or  glazed  only  on  one  face,  or 
on  one  face  and  one  end.  The  color  is  generally  white,  although 
light  blue  and  some  other  colors  can  be  obtained. 

Until  within  a  very  few  years  nearly  all  the  glazed  bricks  used  in 
this  country  were  imported  from  England,  but  there  are  now  some 
eight  or  more  factories  in  this  country  making  them,  and  they  produce 
more  than  half  the  glazed  bricks  now  used  in  the  United  States. 

Enameled  bricks  generally  differ  in  size  from  the  ordinary  bricks. 
The  size  of  the  English  brick  is  3  inches  by  9  inches  by  4^  inches. 
Part  of  the  American  factories  adhere  to  the  English  size,  while 
others  make  the  regular  American  size. 

The  market  price  in  Chicago  for  American  and  English  glazed  and 
enameled  brick  at  the  present  time  is  $120  to  $125  per  M.  for  Eng- 
lish brick  and  $90  to  $110  for  American  brick. 


BRICKWORK.  .      199 

The  American  glazed  bricks  are  now  more  nearly  perfect  than 
when  first  put  on  the  market,  and  appear  to  be  giving  satisfaction. 

The  true  enameled  brick  is  just  as  good  for  external  as  for  interior 
use.  It  will  stand  the  most  severe  and  climatic  changes,  and  may 
be  used  in  any  climate  and  any  situation.  It  is  also  fireproof. 

Both  glazed  and  enameled  bricks  reflect  light,  acquire  no  odor, 
are  impervious  to  moisture  and  form  a  finished  and  highly  ornamental 
surface. 

Use. — Glazed  bricks,  on  account  of  the  above  properties,  are  very 
desirable  for  facing  the  walls  of  interior  courts,  elevator  shafts,  toilet 
rooms,  etc.,  and  especially  for  use  in  hospitals.  They  may  also  be 
used  with  good  effect  in  public  waiting  rooms,  corridors,  markets, 
grocery  and  butter  stores,  and  wherever  a  clean,  light  and  non- 
absorbent  surface  is  desired,  and  also  one  that  will  stand  drenching 
with  water. 

226.  Paving  Bricks. — The  introduction  of  brick  paving  for 
streets  has  led  to  the  manufacture  of  this  class  of  brick  on  an  exten- 
sive scale. 

Paving  bricks  do  not  strictly  come  within  the  province  of  the 
architect,  but  as  he  may  have  occasion  to  use  such  bricks  for  paving 
driveways,  etc.,  it  is  well  to  know  something  about  them. 

Thin  paving  brick  are  also  sometimes  used  for  paving  flat  roofs  of 
office  buildings,  apartment  houses,  etc. 

Paving  bricks  are  most  commonly  made  by  the  stiff  clay  process, 
and  the  bricks,  after  being  cut  from  the  bar,  are  generally,  although 
not  always,  repressed  to  give  them  a  better  shape.  The  clay  used 
for  making  these  bricks  is  generally  shale,  almost  as  hard  as  rock, 
although  it  is  sometimes  found  in  a  semi-plastic  condition.  With  the 
shale  a  certain  proportion — often  30  per  cent. — of  fire  clay  is  gener- 
ally added. 

The  principal  difference  in  the  manufacture  of  paving  brick  from 
common  building  brick  is  in  the  burning.  Paving  brick,  to  stand  the 
frost  and  wear,  must  be  burnt  to  vitrification,  or  until  the  particles  of 
the  body  have  been  united  in  chemical  combination  by  means  of 
heat.  Besides  being  vitrified  paving  brick  are  also  annealed,  or 
toughened,  by  controlling  the  heat  and  permitting  the  bricks  to  cool 
under  certain  conditions. 

Paving  bricks,  to  enable  them  to  endure  the  various  sources  of 
wear  and  disintegration  to  which  they  must  be  exposed  in  a  street 
or  driveway,  or  even  en  a  roof,  must  be  homogeneous  and  compact 
in  texture,  and  must  possess  the  qualities  of  vitrification  and 


aoo  BUILDING  CONSTRUCTION. 

toughness.  They  should  be  free  from  loose  lumps  or  uncrushed 
clay,  or  from  extensive  laminations,  or  fine  cracks  or  checks  of  more 
than  superficial  character  or  extent,  and  should  not  be  so  distorted 
as  to  lay  unevenly  in  the  pavement.  They  should  be  free  from  lime 
or  magnesia  in  the  form  of  pebbles,  and  should  show  no  signs  of  crack- 
ing or  spalling  after  remaining  in  water  ninety-six  hours.  They 
should  have  a  crushing  strength  of  not  less  than  8,000  pounds  per 
square  inch.* 

The  best  test  of  vitrification  is  that  of  porosity.  A  common  hard- 
burnt  brick  may  be  very  dense  and  strong  and  still  absorb  10  or  15 
per  cent,  of  water.  The  same  brick  when  vitrified  will  hold  very 
little  water,  and  should  absorb  none,  in  the  chemical  sense  of  the 
word. 

Engineers,  when  specifying  brick  for  pavements,  generally  limit 
the  absorption  to  4  per  cent.,  and  sometimes  to  2  per  cent.,  the  brick 
to  be  first  dried  to  212°  F.  Paving  bricks  are  made  that  do  not 
absorb  more  than  i  per  cent.  It  is  claimed,  however,  that  a  brick 
may  be  vitrified  and  still  absorb  as  high  as  6  or  8  per  cent.,  owing  to 
its  containing  considerable  air  spaces.  The  density  or  specific  grav- 
ity also  gives  a  valuable  idea  of  the  degree  of  vitrification  of  paving 
brick.  A  great  density  or  high  specific  gravity  usually  indicates 
durability. 

For  testing  the  toughness  and  resistance  to  wear  under  the  horses' 
feet  a  machine  called  a  "  rattler  "  is  used.  The  rattler  resembles  a 
barrel,  and  into  it  several  bricks  are  put  together  with  pieces  of  scrap 
iron  and  the  rattler  is  then  revolved  rapidly  for  a  given  length  of  time. 
The  amount  that  the  bricks  lose  in  weight  is  taken  as  the  test  of  their 
durability. 

It  is  claimed  by  good  authorities  that  the  rattler  test  when  prop- 
erly conducted  is  the  most  important  test  for  durability,  and  that  any 
brick  which  will  successfully  withstand  this  test  will  be  found  sat- 
isfactory. 

227.  Fire  Bricks. — Fire  bricks  are  used  in  places  where  a  very 
high  temperature  is  to  be  resisted,  as  in  the  lining  of  furnaces,  fire- 
places and  tall  chimneys.  The  ordinary  fire  brick  used  for  the  above 
purposes  is  made  from  a  mixture  of  about  50  per  cent,  raw  flint  clay 
and  50  per  cent,  plastic  clay,  the  proportion  varying  with  different 
manufacturers.  The  bricks  are  made  both  by  the  stiff  mud  and  dry 
press  processes,  and  also  by  the  soft  mud  process  with  hand  moulding. 
It  is  claimed  that  the  last  process  gives  the  most  perfect  brick. 

*H.  A.  Wheeler,  E.  M.,  in  the  Clay  Worker,  August,  1895. 


BRICKWORK.  201 

Fire  bricks,  to  admit  of  rapid  absorption  or  loss  of  heat,  should  be 
open  grained  or  porous,  and  at  the  same  time  free  from  cracks. 
They  should  also  be  uniform  in  size,  regular  in  shape,  homogeneous  in 
texture  and  composition,  easily  cut  and  infusible. 

Fire  bricks  are  generally  larger  than  the  ordinary  building  brick. 

228.  Classes  of  Building  Brick.— Common  Brick. — This  term 
includes  all  those  brick  which  are  intended  simply  for  constructional 
purposes,  and  with  which  no  especial  pains  are  taken  in  their  manu- 
facture. There  are  three  grades  of  common  brick,  determined  by 
their  position  in  the  kiln. 

Arch  or  hard  brick  are  those  just  over  the  arch,  and  which,  being 
near  the  fire,  are  usually  heated  to  a  high  temperature  and  often  vit- 
rified. They  are  very  hard,  and  if  not  too  brittle  are  the  strongest 
brick  in  the  kiln.  They  are  often  badly  warped,  so  that  they  can 
only  be  used  for  footings  and  in  the  interior  of  walls  and  piers. 

Red  or  well-burned  brick  should  constitute  about  half  the  brick  in 
the  ordinary  up-draft  kiln,  and  when  made  of  clay  containing  iron 
should  be  of  a  bright  red  color.  For  general  purposes  they  consti- 
tute the.  best  brick  in  the  kiln. 

Salmon  or  soft  brick  are  those  which  form  the  top  of  the  kiln  and 
are  usually  underburned.  They  are  too  soft  for  heavy  work  or  for 
piers,  though  they  may  be  used  for  filling  in  light  walls  and  for  lining 
chimneys. 

The  strength  and  hardness  of  common  bricks  of  all  grades  vary 
greatly  with  the  locality  in  which  they  are  made  on  account  of  the 
difference  in  the  clay.  Some  of  the  salmon  brick  of  New  England 
are  fully  as  hard  and  strong  as  the  red  bricks  of  other  localities;  par- 
ticularly in  the  West.  As  the  color  of  a  brick  may  be  due  more  to 
the  presence  or  absence  of  iron  than  to  the  burning,  it  cannot  be  used 
as  an  absolute  guide  to  the  quality  of  the  brick. 

Stock  brick  are  a  handmade  brick  intended  for  face  work,  and 
with  which  greater  care  is  taken  in  the  manufacture  and  burning 
than  with  common  brick.  In  the  East  they  are  sometimes  called 
face  brick.  . 

Pressed  brick  or  face  brick  generally  refers  to  brick  that  are 
made  in  a  dry  press  machine,  or  that  have  been  repressed.  They 
are  usually  very  hard  and  smooth,  with  sharp  angles  and  corners  and 
true  surfaces  ;  they  may  be  either  stronger  or  weaker  than  common 
brick,  according  to  the  character  of  the  clay  and  the  degree  to  which 
they  are  burnt.  Pressed  brick  are  not  usually  burnt  as  hard  as  com- 
mon brick,  and  are,  therefore,  sometimes  not  as  durable.  Pressed 


202  BUILDING  CONSTRUCTION. 

brick  cost  from  two  to  five  times  as  much  as  common  brick,  and  are. 
therefore,  generally  used  only  for  the  facing  of  the  wall. 

Moulded,  arch  and  circle  brick  are  special  forms  of  pressed  brick. 
A  great  variety  of  moulded  or  ornamental  bricks  are  now  made,  by 
means  of  which  mouldings  and  cornices  may  be  built  entirely  of 
brick.  Most  of  the  companies  manufacturing  pressed  bricks  will  also 
make  any  special  shape  of  brick  from  an  architect's  designs.  Arch 
bricks  are  made  in  the  form  of  a  truncated  wedge  and  are  used  for 
the  facing  of  brick  arches.  They  can  be  made  for  any  radius  desired. 
Circle  brick  are  made  for  facing  the  walls  of  circular  towers,  bays, 
etc.  The  radius  of  the  bay  should  be  given  when  ordering  these 
brick. 

229.  Color  of  Bricks. — The  color  of  common  bricks  depends 
largely  upon  the  composition  of  the  clay  used  and  the  temperature 
to  which  they  are  burnt.     Pure  clay,  free  from  iron,  will  burn  white, 
but  the  color  of  white  bricks  is  generally  due  to  the  presence  of  lime. 
Iron  in  the  clay  produces  a  tint  which  varies  from  light  yellow  to 
orange  and  red,  according  to  the  proportion  of  iron  contained  in  the 
clay.     A  clear  bright  red  is  produced  by  a  large  proportion  of  oxide 
of  iron,  and  a  still  greater  proportion  of  iron  gives  a  dark  blue  or 
purple  color,  and  when  the  bricks  are  intensely  heated  the  iron  melts 
and  runs  through  the  bricks,  causing  vitrification  and  giving  increased 
strength.     The  presence  of  iron  and  lime  produces  a  cream  or  light 
drab  color.     Magnesia  produces  a  brown  color,  and  when  in  the 
presence  of  iron  makes  the  brick  yellow. 

The  color  of  pressed  brick  is,  of  course,  the  same  as  that  of  com- 
mon bricks  made  from  the  same  clay  ;  but  pressed  bricks  are  also 
colored  artificially,  either  by  mixing  together  clays  of  different  chem- 
ical composition,  or  by  mixing  mineral  paints  or  mortar  colors  with 
the  clay  in  the  dry  pan.  Bricks  are  also  sometimes  colored  by 
applying  a  mineral  pigment  to  the  face  of  the  bricks  before  burning. 
This  latter  method,  however,  is  not  very  satisfactory.  At  the  pres- 
ent time  the  use  of  colored  bricks  is  very  popular,  and  face  brick  are 
made  in  all  shades  of  red,  pink,  buff,  cream  and  yellow.  Some  of 
these  colors  are  very  effective  when  used  in  an  artistic  manner,  but 
the  use  of  colored  bricks  has  been  much  abused,  and  it  requires  a 
fine  sense  of  color  to  use  them  effectively,  especially  where  two  or 
more  shades  are  used  in  the  same  building. 

230.  Size  and  Weight  of  Building  Bricks.— In  this  coun- 
try there  is  no  legal  standard  for  the  size  of  bricks,  and  the  dimen- 
sions vary  with  the  maker  and  also  with  the  locality.     In  the  New 


BRICKWORK.  203 

England  States  the  common  brick  averages  about  7^x3^x2^  inches. 
In  most  of  the  Western  States  common  bricks  measure  about 
8^x4^x2^  inches,  and  the  thickness  of  the  walls  measures  about  9, 
13,  18  and  22  inches  for  thicknesses  of  i,  i£,  2  and  2\  bricks.  The 
size  of  all  common  bricks  varies  considerably  in  each  lot,  according 
to  the  degree  to  which  they  are  burnt ;  the  hard  bricks  being  from 
\  to  -fa  of  an  inch  smaller  than  the  salmon  bricks. 

Pressed  brick  or  face  brick  are  more  uniform  in  size,  as  most  of 
the  manufacturers  use  the  same  size  of  mould.  The  prevailing  size 
for  pressed  brick  is  8^x4^x2^  inches.  Pressed  bricks  are  also  made 
\\  inches  thick  and  12x4x1  £  inches,  the  latter  size  being  generally 
termed  Roman  brick,  or  tile. 

Pressed  bricks  should  be  made  of  such  size  that  two  headers  and  a 
joint  will  equal  one  stretcher,  and  it  is  also  desirable  that  the  length 
of  a  brick  should  be  equal  to  three  courses  of  bricks  when  laid.  The 
National  Brickmakers'  Association  in  1887  and  the  National  Traders' 
and  Builders'  Association  in  1889  adopted  8^x4x2^  inches  as  the 
standard  size  for  common  bricks,  and  8f  X4|oc2|-  for  face  bricks. 

As  all  bricks  shrink  more  or  less  in  burning,  it  is  generally  neces- 
sary to  assort  even  pressed  bricks  into  piles  of  different  thicknesses 
in  order  to  get  first-class  work. 

The  weight  of  bricks  varies  considerably  with  the  quality  of  the 
clay  from  which  they  are  made,  and  also  of  course  with  their  size. 
Common  bricks  average  about  4^  pounds  each,  and  pressed  bricks 
vary  from  5  to  5!  pounds  each. 

231.  Requisites  of  Good  Brick. — i.  Good  building  brick 
should  be  sound,  free  from  cracks  and  flaws  and  from  stones  and 
lumps  of  any  kind,  especially  lumps  of  lime. 

2.  To  insure  neat  work  the  bricks  must  be  uniform  in  size  and  the 
surfaces  true  and  square  to  each  other,  with  sharp  edges  and  angles. 

3.  Good  bricks  should  be  quite  hard  and  burnt  so  thoroughly  that 
there  is  incipient  vitrification  all  through  the  brick.     A  sound,  well- 
burnt  brick  will  give  out  a  ringing  sound  when  struck  with  another 
or  with  a  trowel.      A  dull    sound  indicates  a  soft  or  shaky  brick. 
(This  is  a  simple  and  generally  sufficient  test  for  common  bricks,  as 
a  brick  with  a  good  ring  is  ordinarily  sufficiently  strong  and  durable 
for  any  ordinary  work.) 

4.  A  good  brick  should  not  absorb  more  than  one-tenth  of  its 
weight  of  water.     The  durability  of  brickwork  that  is  exposed  to  the 
action  of  water  and  frost  depends  more  largely  upon  the  absorptive 
power  of  the  bricks  than  upon  any  other  condition  ;  hence,  other 


204  BUILDING  CONSTRUCTION. 

conditions  being  the  same,  those  bricks  which  absorb  the  least 
amount  of  water  will  be  the  most  durable  in  outside  walls  and  foun- 
dations. As  a  rule  the  harder  a  brick  is  burnt  the  less  water  it  will 
absorb.  "  Very  soft,  underburned  bricks  will  absorb  from  25  to  35 
per  cent,  of  their  weight  of  water.  Weak,  light  red  ones,  such  as  are 
frequently  used  in  filling  in  the  interior  of  walls,  will  absorb  about  20 
to  25  per  cent.,  while  the  best  bricks  will  absorb  only  4  or  5  per  cent 
A  brick  may  be  called  good  which  will  absorb  not  more  than  10  per 
cent."* 

232.  Strength. — A   good   brick,   suitable   for   piers  and  heavy 
work,  should  not  break  under  a  crushing  load  of  less  than  4,000 
pounds  per  square   inch  ;   any  additional  strength   is  not  of  great 
importance,  provided  the  brick  meets  the  preceding  requirements. 
In  a  wall  the  transverse  strength  is  usually  of  more  importance  than 
the  crushing  strength.     For  a  good  brick  the  modulus  of  rupture 
should  not  be  less  than  720  pounds  ;  or,  in  other  words,  a  brick  8 
inches  long,  4  inches  wide  and  z\  inches  thick  should  not  break 
under  a  centre  load  of  less  than  1,620  pounds,  the  brick  laying  flat- 
ways and  having  a  bearing  at  each  end  of  i  inch  and  a  clear  span  of 
6  inches.     A  first-class  brick  should  carry  2,250  pounds  in  the  centre 
without  breaking,  and  bricks  have  been  tested  which  carried  9,700 
pounds  before  breaking. 

BRICKWORK. 

233.  To  build  any  kind  of  a  brick  structure  so  as  to  make  a  strong 
and  durable  piece  of  work,  it  is  necessary  to  have  a  bed  of  some  kind 
of  mortar  between  the  bricks.     Brickwork,  therefore,  consists  both  of 
bricks  and  mortar,  and  the  strength  and  durability  of  any  piece  of 
work  will  depend  upon  the  quality  of  the  bricks,  the  quality  of  the 
mortar,  the  way  in  which  the  bricks  are  laid  and  bonded  and  whether 
or  not  the  bricks  are  laid  wet  or  dry. 

The  strength  and  stability  of  a  wall,  arch  or  pier  also  depends  upon 
its  dimensions  and  the  load  it  supports,  but  for  the  quality  of  the 
brickwork  only  the  above  items  need  be  considered. 

The  kinds  and  qualities  of  mortars  used  for  laying  brickwork  are 
described  in  Chapter  IV.  The  majority  of  the  brick  buildings  in 
this  country  are  built  with  common  white  lime  mortar,  to  which 
natural  cement  is  sometimes  added.  For  brickwork  below  ground 
either  hydraulic  lime  or  cement  mortar  should  be  used.  (See  Sec- 
tions 107  and  127.) 

*  Ira  O.  Baker,  in  "  Masonry  Construction,"  p.  38. 


BRICKWORK.  205 

The  function  of  the  mortar  in  brickwork  is  threefold,  viz.: 

1.  To  keep  out  wet  and   changes   in   temperature  by  filling  all 
crevices. 

2.  To  unite  the  whole  into  one  mass. 

3.  To  form  a  cushion  to  take  up  any  inequalities  in  the  bricks 
and  to  distribute  the  pressure  evenly. 

The  first  object  is  best  attained  by  grouting,  or  thoroughly  "  flush- 
ing "  the  work  ;  the  second  depends  largely  upon  the  strength  of  the 
mortar,  and  the  third  is  affected  principally  by  the  thickness  of  the 
joints. 

234.  Thickness  of  Mortar  Joints. — Common  brick  should 
be  laid  in  a  bed  of  mortar  at  least  ^  and  not  more  than  f  of  an  inch 
thick,  and  every  joint  and  space  in  the  wall  not  occupied  by  other 
materials  should  be  filled  with  mortar.     The  best  way  of  specifying 
the  thickness  of  the  joint  is  by  the  height  of  eight  courses  of  brick 
measured  in  the  wall.     This  height  should  not  exceed  by  more  than 
2  inches  the  height  of  eight  courses  of  the  same  brick  laid  dry. 

As  common  bricks  are  usually  quite  rough  and  uneven,  it  is  not 
always  easy  to  determine  the  thickness  of  a  single  joint,  but  the  vari- 
ation from  the  specifications  in  any  eight  courses  that  may  be  selected 
should  be  very  slight.  It  is  not  uncommon  to  see  joints  |-  inch  thick 
in  common  brickwork,  especially  where  the  work  is  not  superin- 
tended. 

Pressed  bricks,  being  usually  quite  true  and  smooth,  can  be  laid 
with  a  ^-inch  joint,  and  it  is  often  so  specified.  A  ^-inch  joint  is 
probably  stronger,  however,  as  it  permits  filling  the  joint  better. 

235.  Laying  Brick. — A.  Common  Brick. — The  best  method  of 
building  a  brick  wall  is  to  first  lay  the  two  outside  courses  by  spread- 
ing the  mortar  with  a  trowel  along  the  outer  edge  of  the  last  course 
of  brick  to  form  a  bed  for  the  brick  to  be  laid,  and  scraping  a  dab  of 
mortar  against  the  outer  vertical  angle  of  the  last  brick  laid,  and  then 
pressing  the  brick  to  be  laid  into  its  place  with  a  sliding  motion, 
which  forces  the  mortar  to  completely  fill  the  joint. 

Having  continued  the  two  outer  courses  of  brick  to  an  angle  or 
opening,  the  space  between  the  courses  should  be  filled  with  a  thick 
bed  of  soft  mortar  and  the  bricks  pressed  into  this  mortar  with  a 
downward  diagonal  motion,  so  as  to  press  the  mortar  up  into  the 
joints.  This  method  of  laying  is  called  "shoving."  If  the  mortar 
is  not  too  stiff,  and  is  thrown  into  the  wall  with  some  force,  it  will 
completely  fill  the  upper  part  of  the  joints,  which  are  not  filled  by 
the  shoving  process.  A  brick  wall  laid  up  in  this  way  will  be  very 


206 


B  UILDING  CONS  TR  UC TION. 


strong  and  difficult  to  break  down.  A  very  common  method  of  lay- 
ing the  inside  brick  in  a  wall  is  to  spread  a  bed  of  mortar  and  on  this 
lay  the  dry  brick.  If  the  bricks  are  laid  with  open  joints  and  thor- 
oughly slushed  up  it  makes  very  good  work,  but  unless  the  men  are 
carefully  watched  the  joints  do  not  get  filled  with  mortar,  and  the 
wall  will  not  be  as  strong  as  when  the  bricks  are  shoved. 

236.  Grouting.— Another  method  of  laying  the  inside  brick  is  to 
lay  them  dry  on  a  bed  of  mortar,  as  described  above,  and  then  fill  all 
the  joints  full  of  very  thin  mortar.  This  is  called  grouting,  and, 
while  it  is  condemned  by  many  writers,  the  author  knows  from 
actual  experience  that  when  properly  done  it  makes  very  strong  work. 
No  more  water  than  is  necessary  to  make  the  mortar  fill  all  the  joints 
should  be  used,  and  grouting  should  not  be  used  in  cold  or  freezing 
weather.  Grouting  is  especially  valuable  when  very  porous  bricks 
are  used.  (See  Section  132.) 


237.  Striking  the  Joints. — For  inside  walls  that  are  to  be  plastered 
che  mortar  projecting  from  the  joints  is  merely  cut  off  flush  with  the 
trowel.  For  outside  walls  and  inside  walls,  where  the  brick  are  left 
exposed,  the  joint  should  be  "struck"  as  in  Fig.  122.  This  is  done 
with  the  point  of  the  trowel,  by  holding  the  trowel  obliquely.  Fig.  123 
is  the  easiest  joint  to  make,  and  is  the  one  generally  made  unless 
Fig.  122  is  insisted  on.  For  inside  work  it  makes  no  particular  dif- 
ference which  joint  is  used,  but  for  outside  work  Fig.  122  is  much 
more  durable,  as  the  water  will  not  lodge  in  the  joint  and  soak  into 
the  mortar,  as  will  be  the  case  when  the  joint  is  made  as  in  Fig.  123. 

When  "  struck  joints"  are  desired  they  should  always  be  specified, 
otherwise  the  brick  mason  may  claim  that  he  is  not  obliged  to  strike 
them. 

B.  Face  Brick. — Face  brick  are  usually  laid  in  mortar  made  of 
lime  putty  and  very  fine  sand,  often  colored  with  a  mineral  pigment. 


BRICKWORK.  207 

(See  Sections  104  and  148.)  The  joints  should  not  exceed  T3^  of  an 
inch,  except  in  cases  where  a  horizontal  effect  is  desired,  when  the 
horizontal  joints  are  made  \  of  an  inch  and  the  vertical  joints  as 
close  as  possible.  For  very  fine  work  the  joints  are  sometimes  kept 
down  to  \  of  an  inch.  The  joints  should  be  carefully  filled  with 
mortar  and  either  ruled  at  once  with  a  small  jointer  or  else  raked  out 
and  left  for  pointing.  In  very  particular  work  a  straight-edge  is  held 
under  the  joint  and  the  jointer  drawn  along  on  top  of  it,  thus  mak- 
ing a  perfectly  straight  joint.  This  is  called  rulled  work.  In  laying 
the  soffits  of  arches  and  vaults  with  face  brick  the  joint  cannot  be 
finished  until  the  centre  is  removed,  therefore  the  joint  should  not 
be  quite  filled  with  mortar,  and  must  be  raked  out  and  pointed  after 
the  centre  is  removed 

Many  pressed  brick  and  some  handmade  bricks  have  one  or  more 
depressions  in  the  larger  surfaces  of  the  brick  to  give  a  better  key  to 
the  mortar.  When  the  depressions  are  only  on  one  side  of  the  brick 
that  side  should  be  uppermost. 

When  building  of  face  brick  a  piece  of  brickwork  at  least  2  feet 
high  and  2  feet  6  inches  long  should  be  built  up  in  an  out-of-the-way 
place  as  soon  as  the  first  lot  of  brick  is  delivered,  as  a  sample  piece, 
and  all  stone  or  terra  cotta  work  should  be  made  to  conform  abso- 
lutely to  the  brickwork. 

Sorting. — Pressed  brick,  even  from  the  same  kiln,  generally  vary 
in  size  and  shade,  the  darker  brick  often  being  ^  inch  thinner  than 
the  lighter  brick  and  also  shorter.  If,  therefore,  a  perfectly  uniform 
color  is  desired  the  bricks  must  be  sorted  into  piles,  so  that  each  lot 
will  be  of  the  same  shade,  and  each  shade  laid  in  the  building  by 
itself.  The  change  between  the  different  shades  should  occur,  where 
possible,  at  a  string  course  or  at  an  angle  in  the  building.  Many 
architects,  however,  consider  that  a  handsomer  and  brighter  wall  is 
secured  by  mixing  the  different  shades,  so  that  hardly  two  bricks  of 
exactly  the  same  shade  will  come  together,  although  if  the  mixing  is 
well  done  the  general  tone  of  the  wall  at  a  distance  will  be  uniform. 
With  colored  bricks  this  haphazard  method  undoubtedly  gives  the 
most  artistic  and  sparkling  effect. 

Circular  Work. — For  circular  walls,  faced  with  pressed  brick,  the 
bricks  should  be  made  of  the  same  (or  very  nearly  the  same)  curva- 
ture as  the  wall.  Many  pressed  brick  manufacturers  carry  circle 
brick  of  different  curvatures  in  stock,  and  any  curvature  can  be 
made  to  order. 


ao8  BUILDING  CONSTRUCTION. 

When  circle  brick  cannot  be  obtained  straight  bricks  may  be  used 
for  curvatures  with  a  radius  of  12  feet  o»-  over,  and  for  lesser  radii 
half  brick  or  headers  should  be  used. 

238.  Brick    to    be   Wet. — Mortar,   unless  very  thin,  will   no? 
adhere  to  a  dry,  porous  brick,  because  the  brick  robs  the  mortar  of 
its  moisture,  which  prevents  its   proper  setting.     On   this  account 
brick  should  never  be  laid  dry,  except  in  freeing  weather,  and  in  hot, 
dry  weather  it  is  impossible  to  get  the  bricks  t<x>  wet.     When  using 
very  porous  brick  the  wetting  of  the  brick  is  of  more  consequence  in 
obtaining  a  strong  wall  than  any  other  condition.     As  wetting  the 
bricks  greatly  increases  their  weight  and  consequently  the  labor  of 
handling  them,  besides  making  it  harder  on  the  hands,  masons  do 
not  like  to  wet  them  unless  they  are  obliged  to,  and  it  should  always 
be  specified  and  insisted  upon  by  the  superintendent,  except  In  freez- 
ing weather. 

Pressed  brick  cannot  very  well  be  laid  dry,  and  the  masons  gener- 
ally wet  them  for  their  own  convenience,  but  they  will  often  tell  all 
sorts  of  stories  to  escape  wetting  the  common  brick. 

239.  Laying    Brick    in    Freezing  Weather.  —  Brickwork 
should  never  be  laid  when  the  temperature  is  be'ow  32°,  and  if  it  is 
below  40°  and  liable  to  fall  below  32°  at  night,  salt  should  be  mixed 
with  the  mortar  and  the  bricks  heated  before  laying,  and  the  top  of 
the  wall  covered  with 'boards  and  straw  at  night.     It  is  much  better 
not  to  lay  brick  in  freezing  weather  unless  the  delay  occasioned 
involves  a  great  loss.     In  building  large  buildings  in  the  winter  time 
one-third  Portland  cement  should  be  added  to  the  mortar,  then  it 
will  not  be  damaged  by  freezing.     It  is  necessary  that  the  surface  of 
the  bricks  be  clean  and  free  from  frost,  snow  or  ice,  when  they  are 
laid,  otherwise  the  mortar  will  not  adhere  to  them. 

If  the  mortar  in  the  upper  courses  becomes  frozen  over  night, 
those  courses  should  be  taken  down  and  the  bricks  thoroughly 
cleaned  before  being  used  again.  For  the  effect  of  freezing  on  mor- 
tar see  Section  139. 

Protection  from  Storms. — Wet  without  frost  does  not  injure  the 
strength  of  brickwork,  but  if  rain  strikes  the  top  of  a  wall  it  will  wash 
the  mortar  out  of  the  joints  and  stain  the  face  of  the  wall. 

The  excessive  wetting  of  a  wall  is  also  injurious,  as  it  takes  a  long 
time  for  the  wall  to  dry  out,  and  it  is  likely  never  to  dry  to  a  uni- 
form color.  For  this  reason  the  top  of  the  wall  should  always  be 
protected  at  night,  or  when  leaving  off  work,  by  boards  placed  so  as 
to  shed  the  water. 


BRICKWORK.  209 

240.  Ornamental  Brickwork. — The  ornamental  effects  to  be 
obtained  by  the  varied  use  of  bricks  are  exceedingly  numerous.  First, 
there  are  the  constructive  features,  such  as  arches,  impost  courses, 
pilasters,  belt  and  string  courses,  cornices  and  panels  ;  then  there  is 
a  large  field  for  design  in  surface  ornament,  by  means  of  brick  of 
different  shades  or  color,  laid  so  as  to  form  a  pattern. 

For  the  constructive  features  both  plain  and  moulded  bricks  may 
be  used,  although  only  very  plain  effects  can  be  produced  by  plain 
brick  alone. 

In  nearly  all  of  our  large  cities,  and  especially  those  near  which 
pressed  brick  are  manufactured,  a  great  variety  of  moulded  bricks 
can  be  obtained,  by  means  of  which  it  is  possible  to  construct  almost 
any  moulding,  belt  course,  etc.,  that  may  be  desired. 

Belt  courses  and  cornices,  and  in  fact  any  moulded  work  built  of 
brick,  is  much  cheaper  than  the  same  mouldings  cut  in  stone. 

In  designing  brick  details  a  point  to  be  observed 
is  that  the  projection  should  be  kept  small. 

The  top  of  all  belt  courses  should  have  a  wash 
on  top,  as  shown  in  Fig.  124. 

The  top  course,  W,  should  be  laid  as  stretchers 
when  the  projection  is  not  over  3  inches  to  reduce 
the  number  of  end  joints,  and  the  bricks  should 
also  be  laid  in  cement  mortar,  so  that  the  mortar 
in  the  end  joints  will  not  be  washed  out. 

If  W  is  a  stretcher  course,  at  least  every  other 
brick  in  the  course  below  should  be  a  header. 

If  a  beveled  brick  cannot  be  obtained  for  the  top  course,  and  a 
plain  brick  must  be  used,  its  upper  surface  should  be  protected  by 
sheet  lead  built  into  the  second  joint  above  it,  as  shown  at  A,  Fig.  125, 
or  the  top  of  the  bricks  may  be  plastered  with  Portland  cement,  as 
shown  at  B.  Unless  some  such  precaution  is  taken  to  protect  the 
top  of  the  projecting  brick  from  the  wet,  the  rain  water  will  after  a 
while  soften  the  mortar  in  the  joint,  P,  and  penetrate  into  the  wall. 
The  end  joints  in  the  belt  course  are  always  liable  to  be  washed  out. 
Belt  courses  and  cornices  should  always  be  well  tied  to  the  wall  by 
using  plenty  of  headers  or  iron  ties.  The  top  of  the  wall  should  also 
be  well  anchored  to  the  rafters  or  ceiling  joist  by  iron  anchors,  as  the 
projection  of  the  cornice  tends  to  throw  the  wall  outward. 

In  using  moulded  brick  in  string  courses  and  cornices  it  is  more 
economical  to  use  bricks  that  can  be  laid  as  stretchers,  as  it,  of 


aio  BUILDING  CONSTRUCTION. 

course,  takes  a  less  number  of  stretchers  than  of  headers  to  fill  a  given 
length,  and  the  bricks  cost  the  same. 

One  of  the  greatest  objections  to  brick  mouldings  is  the  difficulty 
of  getting  them  perfectly  straight  and  true.  Nearly  all  moulded 
brick  become  more  or  less  distorted  in  moulding  and  burning,  so 
that  when  laid  the  abutting  ends  do  not  match  evenly,  and  the 

moulding  presents  the  appear- 
7"e  j    Jj^W  ^  ,    t^xx.          ance  shown  in  Fig.  126. 

••0  Some  makes  of  brick,  how- 

ever,  are  quite  free  from  these 
defects,  and  before  selecting 
moulded  bricks  to  be  used  in 
this  way  the  architect  should 
endeavor  to  ascertain  which 
makes  are  the  truest  and  give 
the  most  perfect  work. 

By  being  very  careful  in  lay- 
ing the  bricks  to  average  the  defects,  and  by  ruling  the  joints,  the 
effect  of  the  distortion  may  be  largely  overcome.  Headers  do  not 
show  the  distortion  as  much  as  stretchers. 

241.  Cornices. — For  brick  buildings  with  a  parapet  wall  and 
flat  roof  a  brick  cornice  is  generally  the  most  appropriate  unless  one 
of  terra  cotta  can  be  afforded.  A  brick  cornice  is  certainly  to  be 


Fig.  126. 

preferred  to  one  of  galvanized  iron  or  wood,  as  it  is  more  durable 
and  will  not  require  painting,  besides  being  a  more  appropriate  use 
of  material. 

In  cornices  where  considerable  projection  is  desired  it  is  almost 
always  safe  to  adopt  some  corbeled  treatment,  building  the  corbels 
up  by  slightly  projecting  each  course.  Dentil  courses  in  cornices 
and  string  courses  are  also  very  effective  and  easy  to  lay. 


BRICKWORK. 


211 


2i2  BUILDING  CONSTRUCTION. 

Figs.  127  and  128  are  suggestions  for  moulded  brick  cornices  for 
three  and  four-story  buildings,  and  Fig.  129  one  of  plain  bricks  for  a 
two-story  building  with  a  low  pitch  roof.  Fig.  130  shows  a  section 
of  a  simple  brick  cornice  that  the  author  has  used  on  brick  churches 
having  a  pitch  roof. 

Decorative  brickwork  should  always  be  executed  in  smooth,  regu- 
lar brick  of  even  color,  as  uneven  colors  and  rough  brick  mar  the 
effect  of  light  and  shade  and  detract  from  the  design. 

All  brick  walls  or  cornices  should  be  capped  by  a  projecting  cop- 
ing of  metal,  terra  cotta  or  stone,  provided  with  a  hollow  drip  to 
throw  off  the  water. 


Fig.  130. 

For  brick  cornices  a  copper  or  galvanized  iron  crown  mould,  such 
as  is  shown  in  Figs.  127  and  129,  is  very  appropriate.  The  metal 
should  be  carried  over  the  top  of  the  wall  (if  a  parapet)  and  down  5 
inches  at  the  back. 

If  the  wall  terminates  as  shown  in  Fig.  128  the  upper  courses 
should  be  laid  in  cement  mortar  and  the  top  well  plastered  with 
Portland  cement.  This  will  protect  the  wall  for  several  years,  but  is 
not  as  lasting  as  terra  cotta  or  metal. 

242.  Surface  Patterns.— Surface  patterns,  or  diaper  work,  are 
very  common  in  brick  buildings  in  Europe,  and  they  have  lately  been 
introduced  to  a  considerable  extent  in  this  country. 


BRICKWORK. 


2I3 


Their  chief  object  is  to  give  variety  to  a  plain  waft  space.  When 
used  in  exterior  walls  they  should  not  be  so  marked  as  to  make  the 
pattern  insistent  and  thus  interfere  with  other  features  of  the  building. 


Fig.  131. 

Usually  sorting  the  brick  into  light  and  dark  shades,  or  varying 
the  color  of  the  mortar  in  which  the  pattern  is  laid,  will  be  sufficient 
for  any  surface  decoration,  the  best  success  in  this  class  of  decora- 
tion being  obtained  by  using  comparatively  simple  designs  and  quiet 
contrasts  of  color. 


Fig.  132. 


If  different  colors  are  used  the  greatest  care  must  be  exercised  in 
their  selection,  and  even  with  care  and  thought  it  is  not  granted  to 
all  architects  to  use  color  nicely. 

One  of  the  best  opportunities  for  the  use  of  color  lies  in  the  direc- 
tion of  pattern  work  for  frieze  and  band  courses. 


2I4 


BUILDING  CONSTRUCTION. 


Fig.  131  shows  a  simple  brick  diaper  for  a  frieze,  and  Figs.  132 
and  133  an  ornamental  panel  and  chimney,  the  latter  designed  by 
Mr.  H.  P.  Marshall,  architect. 

Surface  patterns  should  generally  be 
flush  with  the  wall.  When  used  as  in 
Fig.  133  the  pattern  may  project  £  inch 
from  the  surface  or  panels. 

Diaper  work  may  also  be  used  with  good 
effect  on  interior  brick  walls  of  waiting 
rooms,  corridors,  public  baths,  etc. 

CONSTRUCTION  OF  WALLS. 
243.  The  proper  construction  of  a  brick 
building  involves  many  things  besides  the 
mere  laying  of  one  brick  on  top  of  another 
with  a  bed  of  mortar  between.  The  man- 
ner of  laying  or  bedding  the  bricks  and 
the  general  methods  of  doing  the  work  hav- 
ing been  considered,  we  will  next  consider 
the  points  in  construction  required  to 
obtain  a  strong  and  durable  wall,  and  the 
precautions  to  be  observed  to  prevent  set- 
tlements and  cracks  and  adapting  the  work 
to  the  purposes  for  which  it  is  intended. 

Aside  from  the  quality  of  the  materials  and  the  character  of  the 
work,  the  bonding  of  a  wall  has  the  most  to  do  with  its  strength. 

Bond. — Bond  in  brickwork  is  the  arrangement  of  the  bricks 
adopted  for  tying  all  parts  of  the  wall  together  by  means  of  the 


T~r~T~rnr 


i i 


Fig.  134.— Common  Bond. 


Fig-  i33- 


Fig.  135- 


weight  resting  on  the  bricks,  and  also  for  distributing  the  effects  of  a 
concentrated  weight  over  an  ever-increasing  area. 

Common  Bond.—k.  brick  laid  with  its  side  parallel  to  the  face  of 
the  wall  is  called  a  stretcher  j  when  laid  at  right  angles  to  the  wall. 


BRICKWORK.  215 

so  that  its  end  is  parallel  to  the  face  of  the  wall,  it  is  called  a  header. 
Common  brick  walls  in  this  country  are  almost  universally  built  by 
laying  the  brick  all  stretchers  for  from  four  to  six  courses  and  then 
laying  a  course  of  headers  as  shown  in  Fig.  134.  When  the  wall  is 
jnore  than  one  brick  in  thickness  the  heading  courses  should  be 
arranged  either  as  at  A  or  JS,  Fig.  135.  For  first-class  work  the  wall 
should  be  bonded  with  a  heading  course  every  sixth  course. 


'       ..       I 


Fig.  136.— Plumb  Bond. 

244.  Plumb  or  diagonal  bond  (sometimes  called  American  bond)  is 
generally  used  when  the  wall  is  faced  with  pressed  brick.  The  face 
brick  are  laid  all  stretchers  with  the  joints  plumb  above  each,  other 
from  bottom  to  top  of  the  wall,  as  shown  at  A,  Fig.  136.  The  bond- 
ing of  the  face  brick  to  the  common  brick  is  accomplished  by  clip- 
ping off  the  back  corners  of  the  face  brick  in  every  sixth  or  seventh 
course  and  laying  diagonal  headers  behind,  as  shown  at  B,  Fig.  136. 

This  does  not  make  as  strong  a  tie 
as  a  regular  header,  but  if  carefully 
done  it  appears  to  answer  the  pur- 
pose. Very  often  where  this  bond 
is  used  only  one  corner  of  each  face 
brick  in  the  outside  course  is 
clipped,  so  that  only  half  as  many 
F;g  137.  diagonal  brick,  or  headers,  as  are 

indicated    in    F.ig.    136    are    used. 

This  of  course  does  not  make  as  strong  a  bond  as  when  both  of  the 
back  corners  are  clipped.  In  walls  exceeding  one  story  in  height  the 
architect  should  see  that  both  corners  are  clipped.  The  strongest 
method  of  bonding  for  face  brick  is  by  the  Flemish  or  cross  bond, 
described  in  Section  245.  The  objection  to  these  bonds,  however,  is 
the  increased  expense  occasioned  by  using  so  many  face  brick  head- 
ers and  also  that  the  face  brick  and  common  brick  do  not  usually  lay 
to  the  same  heights,  so  that  it  would  be  necessary  to  clip  the  com- 
mon brick  if  face  brick  headers  were  used  in  every  course,  or  even 
every  third  or  fourth  course. 


2t6 


BUILDING  CONSTRUCTION. 


Face  bricks,  when  laid  as  in  Fig.  136,  are  often  tied  to  the  back- 
ing by  pieces  of  galvanized  iron  or  tin  (as  shown  in  Fig.  137),  which 
have  their  ends  turned  over  a  stiff  wire  about  4  inches  long.  The 
wire  is  not  absolutely  essential,  but  should  always  be  used  in  first- 


Fig.  138. 

class  work.     A  still  better  tie  for  bonding  face  brick  to  the  backing 
is  the  Morse  Wall  Tie,  shown  in  Fig.  138. 

This  tie  is  made  from  -£%  and  -^-inch  galvanized  steel  wire  7,  9,  12 
and  1 6  inches  in  length.  The  ^g-inch  wire  is  used  for  ordinary 
pressed  brickwork,  and  the  J-inch  size  for  very  closely  laid  work.  It 
is  now  very  extensively  used  in  the  Eastern  portion  of  the  country. 


J ,  I    11 


Fig.  i39--English  Bond. 


II 

n          i     ii 

L 

ii     ii         H 

1 

1         n     ii 

II 

i     ii         ii  i 

1 

Ji         ii  ,  ii     , 

II 

i     ii         it  i 

Fig.  140.— Flemish  Bond. 


One  advantage  obtained  in  using  the  metal  tie  is  that  it  is  not  nec- 
essary that  the  joints  in  the  face  work  and  backing  shall  be  on  the 
same  level,  as  the  ties  can  be  bent  to  conform  to  the  difference  in 
level,  as  shown  in  Fig.  137.  Face  brick  bonded  in  this  way  should 
be  tied  at  least  every  fourth  course  with  one  tie  to  each  face  brick. 

245.  English  bond  (Fig.  139)  is  a  method  of  bonding  much  used 
in  England,  and  consists  of  alternate  heading  and  stretching  courses. 


BRICKWORK.  217 

It  is  probably  the  strongest  method  of  bonding  common  brick,  but  it 
is  not  applicable  where  face  brick  are  used.  It  does  not  make  very 
attractive  work,  and  is  scarcely  ever  used  in  this  country. 

Flemish  bond,  shown  in  Fig.  140,  consists  of  alternate^headers  and 
stretchers  in  every  course,  every  header  being  immediately  over  the 
centre  of  a  stretcher  in  the  course  below  ;  closers  (a)  are  inserted  in 
alternate  courses  next  to  the  corner  headers  to  give  the  lap.  This 
makes  a  very  strong  bond,  but  cannot  be  used  with  face  brick  unless 
the  common  brick  are  a  little  smaller  than  the  face  brick,  so  as  to  lay 
up  even  courses.  A  modification  of  this  bond,  consisting  of  laying 
every  fifth  course  of  alternate  headers  and  stretchers,  is  sometimes 
adopted.  It  makes  stronger  work  than  the  diagonal  bond  and  looks 
about  as  well. 

English  cross  bond  is  a  variety  of  English  bond  said  to  be  much  used 
in  Holland,  its  name  being  suggested  by  the  appearance  of  the  sur- 
face, on  which  the  bricks  seem  to  arrange  themselves  into  St.  Andrew's 

crosses.  It  only  differs  from  ordinary 

•^  I  II  I  "  II  'I — H  English  bond  in  that  the  stretchers 


"ini       II    ~~\       (I       ||       Ip    of   the    successive   stretching    courses 

-11 — i1     „     II      i    'I    I,     'I          Hi  L,     "          ,  .     . 


I        '      \_  I      _  break   joint   with   each    other  on  the 


JLJI       II       II       II       |[      j       face  of  the  wall,  as  well  as  with  the 


J 1' II II  headers   in    the  adjoining   courses,  as 


Fig.  14,  -Cross  Bond.  ghown    JR     pig 

much  better  looking  wall  than  the  ordinary  English  bond. 

246.  Hoop  Iron  Bond. — Pieces  of  hoop  iron  are  often  laid  flat 
in  the  bed  joints  of  brickwork  to  increase  its  longitudinal  tenacity 
and  prevent  cracks  from  unequal  settlement.     The  ends  of  the  iron 
should  be  turned  down  about  2  inches  and  inserted  into  the  vertical 
joints.     Nothing  less  than  No.  18  iron  should  be  used,  and  the  hold- 
ing power  of  the  ties  may  be  greatly  improved  by  dipping  in  hot  tar 
and  then  covering  with  sand.     Hoop  iron  bond  is  strongly  to  be  rec- 
ommended for  strengthening  brick  arches  and  the  walls  above,  also 
the  walls  of  towers,  etc.,  and  where  an  interior  wall  joins  an  external 
wall.     Twisted  iron  bars  are  still  better  for  this  purpose. 

247.  Anchoring  the  Wall. — Although  this  belongs  more  espe- 
cially in  the  carpenter  work,  it  is  mentioned  here  as  a  very  important 
point  in  securing  the  stability  of  the  wall  and  preventing  its  inclin- 
ing outward. 

Brick  walls  should  be  tied  to  every  floor  at  least  once  in  every  6 
lineal  feet,  either  by  iron  anchors,  solidly  built  into  the  wall  and 
spiked  to  the  floor  joist,  or  by  means  of  a  box  anchor  or  joist  hanger. 


218 


BUILDING  CONSTRUCTION. 


The  forms  of  iron  anchors  most  commonly  used  for  this  purpose 
are  those  shown  in  Fig.  142,  the  one  shown  at  a  being  the  most  com- 
mon, and  about  as  good  a  style  as  any.  The  anchor  shown  at  b 
answers  equally  as  well,  but  costs  a  very  little  more.  Anchors  like  a 
and  b  are  spiked  to  the  sides  of  the  floor  joist  and  built  into  the  wall, 
as  shown  in  Fig.  143. 

If  the  wall  is  a  side  or  rear  wall,  where  the  appearance  is  not  of 
much  consequence,  it  is  better  to  have  the  anchor  pass  clear  through 
the  wall,  with  a  plate  on  the  outside,  as 
such  an  anchor  gets  a  much  better  hold 
on  the  wall  than  is  possible  when  it  is 
built  into  the  middle  of  the  wall.  The 
cheapest  form  of  anchor  for  this  purpose 
is  that  shown  at  c,  which  has  a  thin  plate 
of  iron  doweled  and  upset  on  the  outer 
end.  This  style  of  anchor  may  also  be 
used  for  building  into  the  middle  of  the 
wall. 

For  anchoring  the  ends  of  girders,  or 
where   a   particularly  strong    anchor  is 
desired,  the  form  shown  at  d  is  undoubt- 
edly  the   best.     This   anchor   is    made 
from  a  f-inch    bolt,    flattened    out    for 
spiking  to  the  joist  and  provided  with  a 
cast  iron  star  washer.     It  possesses  the 
advantage  of  having  a  nut  on  the  outer 
end,    which    can    be    tightened    up    if 
desired  after  the  wall  is  built. 
All  of  these  anchors  should  be  spiked  to  the  side  of  the  joist  or 
girder,  near  the  bottom,  as  shown  in  Fig.  143.     The  nearer  the  anchor 
is  placed  to  the  top  of  the  joist,  the  greater  will  be  the  destructive 
effect  on  the  wall  by  the  falling  of  the  joist,  as  shown  in  Fig.  143  A. 
For  anchoring  walls  that  are  parallel  to  the  joist  the  anchor  must 
be  spiked  to  the  top  of  the  joist,  and  should  either  be  long  enough  to 
reach  over  two  joist,  or  a  piece  of  ij-inch  board  should  be  let  into 
the  top  of  three  or  four  joist  and  the  anchor  spiked  to  it. 

Any  of  these  forms  of  anchors  have  the  objection  that  in  case  the 
beams  fall  during  a  severe  fire  or  from  any  other  cause  they  are  apt 
to  pull  the  wall  over  with  them.  To  overcome  this  objection,  as  well 
as  to  secure  other  advantages,  the  Duplex  Wall  Hanger,  shown  in 
Fig.  144,  and  the  Goetz  Box  Anchor,  shown  in  Fig.  145,  have  been 


BRICKWORK. 


219 


invented.     These  devices  hold  the  timber  by  means  of  a  rib  or  lug 
gained  into  its  lower  edge.     The  anchoring  is  not  as  efficient  per- 
haps as  is  secured  by  the  anchors  shown  in   Fig.  142   but  is  ample 
for  all  ordinary  conditions,  especially  as 
when  these  devices  are  used  every  joist 
is  anchored. 

These  devices  also  offer  the  additional 


Fig.  143- 


Fig.  i«  A. 


advantages  that  they  do  not  weaken  the  wall,  while  they  increase  the 
bearing  of  the  timbers  and  reduce  the  possibility  of  dry  rot  to  a  min- 
imum. They  also  permit  of  easily  replacing  the  joist  after  a  fire. 

The  Duplex  Wall  Hanger  is  especially  desirable  for  party  and  par- 
tition walls,  as  it  obviates  the  necessity  of  building  the  beams  into 


Fig.  144- 


Fig.  MS- 


the  wall  and  permits  the  wall  to  be  as  solid  at  the  floor  levels  as  in. 
other  portions.     (See  Fig.  146.) 

The  importance  of  anchoring  the  joist  to  the  walls,  and  thus  pre- 
venting the  walls  from  being  thrown  outward  either  from  settlement 
in  the  foundation  or  from  pressure  exerted  against  the  inside  of  the 
wall,  is  very  great,  and  should  not  be  overlooked  by  the  architect. 
Many  walls  have  either  fallen,  or  had  to  be  rebuilt,  that  might  have 
been  saved  by  proper  anchoring. 


220 


BUILDING  CONSTRUCTION. 


Fig.  146. 


248.  Corbeling  the  Wall  for  Floor  Joist.— In  some  local- 
ities it  is  the  custom  to  form  a  ledge  to  support  the  floor  joist  by 
means  of  a  continuous  corbel  of  three  or  more  courses.     This  is  done 
to  prevent  weaking  the  wall  by  the  ends  of  the  floor  timbers,  for,  of 

course,  wherever  wooden  tim- 
bers are  built  into  a  wall  they 
lessen  the  section  or  bearing 
area  of  the  wall  by  just  the 
amount  of  space  taken  up  by 
the  timbers,  and  in  partition 
walls  this  is  very  considerable. 
The  Chicago  Building  Ordi- 
nance provides  that  all  walls 
of  warehouses,  16  inches  or 
less  in  thickness,  and  all  walls 

of  dwellings,  12  inches  or  less  in  thickness,  shall  have  ledges  4  inches 

wide  to  support  the  floor  joist,  and  in  all  cases  where  ledges  are  built 

they  are  to  be  carried  to  the  top  of  the  joist,  as  shown  in  Fig.  147. 
When  walls  are  corbeled  in  this  way  it  requires  a  plaster  or  wooden 

cornice,  as  shown  by  the  dotted  line,  to  give  a  proper  finish  for  the 

angles  of  the  rooms,  and  for  this 

reason   corbeling   is  not  usually 

done  where  not  required  by  law. 
Corbeling  for  floor  joist  should 

not  be  attempted   with   soft   or 

poor  bricks. 

249.  Walls  to  be  Carried 
Up    Evenly.— The   walls   of  a 
building   should  be    carried    up 
evenly,  no  part  being  allowed  to 
be  carried   up  more  than  3  feet 


above  the  rest,  except  where  it  is 
stopped  by  an  opening.  Build- 
ing one  part  of  a  wall  up  ahead 


Fig.  147. 


of  the  rest  produces  unequal  settlement,  and,  the  joints  in  the 
higher  part  setting  before  the  rest  is  added  to  it,  the  work  laid  last  is 
apt  to  settle  away  from  the  other  and  weaken  the  wall,  besides  mar- 
ring the  appearance  of  it.  Whenever  it  is  necessary  to  carry  one  part 
of  a  wall  higher  than  the  rest  the  end  of  the  high  part  should  be 
stepped  or  racked  back,  and  not  run  up  vertically,  with  only  tooth- 
ings left  for  connecting  the  rest  of  the  work. 


BRICKWORK. 


250.  Bonding  of  Walls  at  Angles. — An  important  feature  in 
the  construction  of  brick  buildings  is  the  secure  bonding  of  the  front 
and  rear  walls  to  side  or  partition  walls.  When  practicable  both  walls 
should  be  carried  up  together,  so  that  each  course  of  brick  may  be  well 
bonded.  If  to  avoid  delay  the  side  wall  must  be  built  up  ahead  of  the 
front  wall,  the  end  of  the  side  wall  should  be  built  with  toothings,  as 
shown  in  Fig.  148,  eight  or  nine  courses  high,  into  which  the  backing 
of  the  front  wall  should  be  bonded.  In  addition  to  the  brick  bonding 
anchors  made  of  |x2-inch  wrought  iron,with  one  end  turned  up  2  inches 
and  the  other  welded  around  a  |-inch  round  bar,  should  be  built  into 
the  side  wall  about  every  5  feet  in  height,  as 
shown  in  the  figure.  The  anchors  should  be 
of  such  length  that  the  rod  will  be  at  least  8 
inches  in  from  the  back  of  the  front  wall 
and  extend  at  least  17  inches  into  the  side 
wall.  The  building  regulations  of  most  of 
the  larger  cities  require  that  all  intersecting 
brick  walls  shall  be  tied  together  in  this  way. 
251.  Openings  in  Walls. — The  loca- 
tion of  all  door  and  window  openings  in 
brick  walls  should  be  carefully  considered, 
not  only  as  regards  convenience,  but  also  as 
to  their  effect  on  the  strength  of  the  walL 

oj  L      i  The  combined  width  of  the  openings  in  any 

bearing  wall  should  not  much  exceed  one- 
fourth  of  the  length  of  the  wall,  and  as  far 
as  possible  the  openings  in  the  different 
stories  should  be  over  each  other.  Especially  avoid  placing  a  win- 
dow either  under  a  pier  or  directly  over  a  narrow  mullion,  as  at  a  or 
b,  Fig.  149.  If  windows  must  be  used  in  these  positions,  steel  beams 
should  be  placed  over  the  windows  a  and  c,  as  a  stone  lintel  or  brick 
arch  would  be  quite  sure  to  crack  from  the  combined  effects  of  the 
load  and  the  settlement  of  the  joints  in  the  brickwork  on  either  side 
of  the  window. 

All  openings  in  exterior  walls  should  either  have  relieving  arches 
or  cast  iron  or  steel  beams  behind  the  stone  cap  or  face  arches. 
Ordinary  relieving  arches  (see  Section  265)  are  commonly  used 
where  the  width  of  the  opening  is  less  than  6  feel,  and  steel  beams 
for  greater  widths.  In  bearing  walls,  where  the  top  of  the  openings 
come  within  12  inches  of  the  bottom  of  the  floor  joist,  it  is  hardly 
safe  to  use  relieving  arches,  unless  the  floor  loads  are  very  light. 


B  UILDING  CONS  TR  UC  TION. 


For  door  openings  in  unplastered  brick  partitions  cast  iron  lintels 
may  be  used  to  good  advantage,  as  they  give  a  smooth,  level  soffit  to 
the  opening  and  show  only  a  narrow  strip  of  metal  on  the  face  of  the 
wall. 

252.  Joining  New  Walls  to  Old. — When  a  new  wall  is  to  be 
joined  to  an  old  one,  at  right  angles,  a 
groove  should  be  cut  in  the  old  wall  sim- 
ilar to  that  shown  in  Fig.  1 18  for  the  new 
wall  to  fit  into  and  to  allow  of  its  settling 
independently.  A  cheaper  method,  and 
one  more  commonly  used  in  light  work, 
is  to  nail  a  scantling,  or  2x4,  to  the  wall 
of  the  old  building,  so  that  it  will  come 
in  the  centre  of  the  new  wall,  as  shown  in 
Fig.  150.  A  similar  method  can  be  used 
for  jointing  the  ends  of  an  old  and  new 
wall.  New  work  should  never  be  toothed 
to  old  work  unless  the  new  work  is  laid  in 
cement. 

253.  Thickness  of  Walls.— There 
is  no  practical  rule  by  which  it  is  possible 
to  calculate  the  necessary  thickness  of  brick  walls,  as  the  resistance 
to  crushing,  which  is  the  only  direct  strain,  is  usually  only  a  minor 
consideration. 

We  must  therefore  rely  principally  upon  experience  in  determin- 
ing the  thickness  of  walls  for  any  given 
building,   unless   the   construction   of   the 
building    is   controlled    by   municipal    or 
State  regulations. 

In  nearly  all  of  the  larger  cities  of  the 
country  the  minimum  thickness  of  the 
walls  is  prescribed  by  law  or  ordinance, 
and  as  these  requirements  are  generally 
ample  they  are  usually  adhered  to  by  archi- 
tects when  designing  brick  buildings. 

Table  IX.  gives  a  comparison  of  the 
thickness  of  walls  required  for  mercantile  buildings  in  the  repre- 
sentative cities  of  the  different  sections  of  the  United  States,  and 
affords  about  as  good  a  guide  as  any  to  the  young  architect.  Walls 
for  dwellings  are  generally  permitted  to  be  4  inches  less  than  the 
thicknesses  given  in  the  table. 


Fig.  149. 


Fig.  150. 


BRICKWORK. 


223 


TABLE  TX.— THICKNESS  OF  WALLS  IN  INCHES  FOR  WAREHOUSES,  ETC. 


HEIGHT 
OF  BUILDING. 

STORIES. 

1st 

Id 

3d 

4th 

Itll 

;tii 

-th 

sth 

Ith 

0 

itii 

2th 

Two  Stories. 
Three  Stories. 
Four  Stories. 
Five  Stories. 
Six  Stories. 
Seven  Stories. 
Eight  Stories. 
Nine  Stories. 

Ten  Stories. 

• 

Boston  .  .  . 
New  York  . 
Chicago  .  . 
Minneapolis 
Memphis  .  . 
Denver  .  . 

Boston  .  .  . 
New  York  . 
Chicago  .  . 
Minneapolis 
Memphis  . 
Denver  .  .  . 

Boston  .'.  . 
New  York  . 
Chicago  .  . 
Minneapolis 
Memphis  .  . 
Denver.  .  . 

Boston  .  .  . 

6 

2 
2 

2 

8 
3 

o 
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224  BUILDING  CONSTRUCTION. 

In  compiling  this  table  the  top  of  the  second  floor  was  taken  at  19 
feet  above  the  sidewalk,  and  the  height  of  the  other  stories  at  13  feet 
4  inches,  including  the  thickness  of  the  floor,  as  the  New  York  and 
Boston  laws  give  the  height  of  the  walls  in  feet  instead  of  in  stories. 
When  the  height  of  stories  exceeds  these  measurements  the  thickness 
of  the  walls  in  some  cases  will  have  to  be  increased. 

The  maximum  height  of  stories  permitted  by  the  Chicago  ordi- 
nance with  these  thicknesses  of  walls  is  18  feet  in  first  story,  15  feet 
in  second  story,  13  feet  6  inches  in  the  third  and  12  feet  in  the  stories 
above. 

Although  there  is  a  great  difference  in  the  thicknesses  given  in  the 
table,  more  indeed  than  there  should  be,  yet  a  general  rule  might  be 
deduced  from  the  table,  for  mercantile  buildings  over  four  stories  in 
height,  which  would  be  somewhat  as  follows : 

For  brick  equal  to  those  used  in  Boston  or  Chicago  make  the 
thickness  of  the  three  upper  stories  16  inches,  of  the  next  three  below. 
20  inches,  the  next  three  24  inches  and  the  next  three  28  inches. 
For  a  poorer  quality  of  material  make  only  the  two  upper  stories  16 
inches  thick,  the  next  three  20  inches  and  so  on  down. 

In  buildings  less  than  five  stories  in  height  the  top  story  may  be 
12  inches  in  thickness. 

For  the  walls  of  dwellings,  13  inches  and  9  inches  may  be.  used  for 
two-story  buildings  ;  for  three-story  buildings  the  walls  should  be  13 
inches  thick  the  entire  height  above  the  basement,  and  for  four-story 
buildings  17  inches  in  first  story  and  13  inches  the  entire  height 
above. 

In  determining  the  thickness  of  walls  the  following  general  prin- 
ciples should  be  recognized  : 

First.  That  walls  of  warehouses  and  mercantile  buildings  should 
be  heavier  than  those  used  for  living  or  office  purposes. 

Second.  That  high  stories  and  clear  spans  exceeding  25  feet 
require  thicker  walls. 

Third.  That  the  length  of  the  wall  is  a  source  of  weakness,  and 
that  the  thickness  should  be  increased  4  inches  for  every  25  feet  over 
100  or  125  feet  in  length.  (In  New  York  the  thicknesses  in  the 
table  must  be  increased  for  buildings  exceeding  105  feet  in  depth. 
In  the  Western  cities  the  tables  are  compiled  for  warehouses  125  feet 
in  depth,  as  that  is  the  usual  depth  of  lots  in  those  cities.) 

Fourth.  That  walls  containing  over  33  per  cent,  of  openings  should 
be  increased  in  thickness. 


BRICKWORK.  22$ 

Fifth.  Partition  walls  may  be  4  inches  less  in  thickness  than  the  out- 
side walls  if  not  over  60  feet  long,  but  no  partition  to  be  less  than  8 
inches  thick. 

PARTY  WALLS. 

There  is  much  diversity  in  building  regulations  regarding  the 
thickness  of  party  walls,  although  they  all  agree  in  that  such  walls 
should  never  be  less  than  12  inches  thick.  About  one-half  of  the 
laws  require  the  party  walls  to  be  of  the  same  thickness  as  external 
walls  ;  the  remainder  are  about  equally  divided  between  making  the 
party  walls  4  inches  thicker  or  thinner  than  for  independent  side 
walls. 

When  the  walls  are  proportioned  by  the  rule  previously  given,  the 
author  believes  that  the  thickness  of  the  party  walls  should  be 
increased  4  inches  in  each  story.  The  floor  load  on  party  walls  is 
obviously  twice  that  on  side  walls,  and  the  necessity  for  thorough 
fire  protection  is  greater  in  the  case  of  party  walls  than  in  other  walls. 

254.  Curtain  Walls. — In  buildings  of  the   skeleton    type    the 
outer  masonry  walls  are  usually  supported  either  in  every  story  or 
every  other  story  by  the  steel  framework,  and  carry   nothing  but 
their  own  weight.     Such  walls  may,  therefore,  be  considered  as  only 
one  or  two  stories  high,  and  are  usually  made  only  12  inches  thick 
for  the  whole  height  of  a  twelve  or  fifteen-story  building. 

255.  Wood  in  Walls. — As  a  rule,  no  more  woodwork  should 
be  placed  in  a  brick  wall  than  is  absolutely  necessary.     Wooden  lin- 
tels for  supporting  brick  walls  are  objectionable  not  only  on  account 
of  their  being  combustible,  but  also  on  account  of  their  shrinkage. 
It  is  generally  impossible  to  obtain  framing  lumber  that  is  thor- 
oughly dry,  and  when  a  brick  wall  is  partially  supported  by  a  wooden 
lintel  a  crack  is  quite  sure  to  develop  sooner  or  later  in  the  manner 
shown  in  Fig.  151.     The  crack  is  obviously  caused  by  the  shrinkage 
of  the  lintel,  which  permits  the  portion  of  the  wall  supported  on  it  to 
settle  by  an  amount  equal  to  the  shrinkage  of  the  wood,  while  the 
portion  of  the  wall  a,  being  supported  on  the  brick  pier,  does  not 
settle. 

Bond  timbers,  or  pieces  of  studding  laid  under  the  ends  of  the  floor 
joist,  are  also  objectionable,  for  the  reason  that  they  are  quite  sure 
to  shrink,  and  thus  leave  the  wall  above  them  unsupported.  Bond 
timbers  are  very  convenient  for  the  carpenters,  as  they  give  a  level 
bearing  for  the  floor  joist,  and  thev  also  distribute  the  weight  over 
the  brickwork,  but  they  should  never  be  used  in  buildings  over  two 


226 


BUILDING  CONSTRUCTION. 


stories  in  height,  or  in  walls  less  than  12  inches  thick.  If  used  at  all 
they  should  be  selected  from  the  dryest  lumber  that  can  be  obtained. 

For  the  proper  use  of  wooden  lintels  under  relieving  arches  see 
Section  265. 

Strips  of  wood  are  sometimes  built  into  walls  to  form  a  nailing  for 
the  wood  finish  or  for  the  furring  strips.  Such  strips  should  not  be 
used  in  buildings  over  two  stories  in  height,  and  should  not  be  over 
•f  inch  thick,  so  that  they  may  take  the  place  of  the  mortar -joint. 

Wooden  bricks,  or  blocks  of  wood  of  the  size  of  a  brick,  are  also 
sometimes  built  into  brick  walls  to  provide  nailings  for  furring  strips, 
door  frames,  etc.  These  not  only  tend  to  weaken  the  wall,  but  they 
generally  shrink  so  as  to  become  loose,  thereby  losing  their  holding 
power.  If  the  bricks  are  so  hard  that  nails  cannot  be  driven  into 
them,  and  the  mortar  is  too  poor  to  hold  the  nails,  then  porous  terra 
cotta  blocks  should  be  used  for  nailing  strips  in  first-class  work. 

Porous  terra  cotta  will  hold  a  nail  almost  like  a  board,  and  has 
none  of  the  objections  common  to  wood. 


Fig.  152. 

256.  Cracks  in  Walls. — It  is  a  very  common  thing  to  see 
cracks  in  brick  walls.  These  cracks  may  be  produced  by  either  one 
of  several  causes. 

Probably  the  most  frequent  cause  of  the  cracking  of  masonry  walls 
is  the  settlement  of  the  foundations,  either  from  their  being  improp- 
erly designed  or  from  the  settlement  of  the  ground  caused  by  wet. 
A  strict  observance  of  the  principles  laid  down  in  Sections  24,  29 
and  30  will  generally  prevent  cracks  starting  from  the  foundation. 

The  effect  produced  on  certain  soils  when  they  become  saturated 
with  water  is  described  in  Section  9. 

Next  to  faulty  foundations,  the  most  common  cause  of  cracks  in 
brick  walls  is  probably  the  use  of  wooden  lintels,  as  described  in  Sec- 
tion 255. 


BRICKWORK.  227 

Besides  the  cracks  that  occur  from  these  causes,  cracks  often  occur 
over  openings  from  settlement  of  the  mortar  joints  in  the  piers  or 
from  spreading  of  the  arches. 

It  is  very  common  to  see  a  small  crack  just  above  the  end  of  a 
door  or  window  sill,  as  shown  in  Fig.  152.  Such  cracks  generally 
occur  near  the  bottom  of  high  walls,  and  are  caused  by  the  compres- 
sion of  the  mortar  in  the  lower  joints  of  the  pier.  They  may  be 
avoided  by  using  slip  sills,  as  described  in  Section  191. 

Another  place  where  cracks  produced  by  the  settlement  of  mortar 
joints  sometimes  occur  is  where  a  low  wall  joins  a  very  high  one.  To 
prevent  such  cracks  the  walls  should  be  joined  by  a  slip  joint,  as  de- 
scribed in  Section  206. 

Generally  cracks  are  more  likely  to  occur  in  walls  that  are  broken 
by  frequent  openings  than  in  a  plain,  unbroken  wall. 

The  use  of  plenty  of  anchors  and  thorough  bonding  will  do  much 
toward  preventing  cracks. 

257.  Damp-proof  Courses. — When  buildings  are  built  on 
ground  that  is  continually  moist  or  wet  the  moisture  is  very  apt  to 
soak  up  into  the  walls  from  the  foundations,  rendering  the  building 
unhealthy  and  often  causing  the  woodwork  to  rot.  To  prevent  the 
moisture  rising  in  this  way  a  horizontal  damp-proof  course  should  be 
inserted  in  all  walls  below  the  level  of  the  first  floor  joist.  It  should 
be  at  least  6  inches  above  the  highest  level  of  the  soil  touching  any 
part  of  the  outer  walls,  and  should  run  unbroken  all  around  them 
and  at  least  2  feet  into  all  the  cross  walls  ;  and  on  very  wet  ground, 
where  the  water  is  but  a  few  feet  below  the  surface,  it  should  be  con- 
tinuous through  all  the  walls.  In  buildings  finished  with  parapet 
walls  it  is  also  desirable  to  insert  a  damp-proof  course  just  above  the 
flashing  of  the  roof  or  gutter  to  prevent  the  wet  from  soaking  'down 
into  the  woodwork  of  the  roof  and  into  the  walls  below. 

Materials. — These  damp-proof  courses  may  be  formed  of  either  of 
the  following  materials  : 

Asphalt. — A  layer  of  rock  asphalt  f  of  an  inch  thick  makes  the  best 
damp-proof  course,  and  should  be  used  for  all  first-class  buildings. 
The  surface  to  receive  the  hot  asphalt  should  be  quite  dry  and  should 
be  made  smooth  to  economize  material,  and  all  the  joints  should 
be  well  flushed  up  with  mort,ar.  The  best  asphalts  for  this  purpose 
are  the  natural  rock 'asphalt  from  Seyssel,  Val  de  Travers  or  Ragusa, 
which  are  imported  into  this  country  in  the  shape  of  blocks  and 
cakes.  When  used  the  cakes  are  melted  in  large  kettles,  mixed  with 
a  small  proportion  of  coal  tar  and  applied  hot.  One  or  two  lay e IT  of 


228  BUILDING  CONSTRUCTION. 

tarred  felt  imbedded  in  the  hot  asphalt  may  also  be  used  with  good 
results. 

"  Roofing  slates,  or  even  hard  vitrified  bricks,  two  courses  break- 
ing joint,  laid  in  half  cement  and  sand  mortar,  or  such  bricks  laid 
without  any  mortar  in  the  vertical  joints,  form  an  inexpensive  damp 
course."  Glass  is  also  sometimes  used  for  this  purpose. 

Portland  Cement. — A  |-inch  layer  of  Portland  cement  mortar, 
mixed  in  the  proportion  of  i  part  cement  and  i  of  sand,  will  often 
answer  the  purpose,  but  is  not  as  desirable  as  the  materials  mentioned 
above. 

HOLLOW  WALLS. 

258.  Their  Object. — It  is  well  known  that  a'  solid  brick  wall 
readily  absorbs  moisture  and  transmits  heat  and  cold.  A  driving 
rainstorm  will  often  penetrate  a  1 2-inch  brick  wall  so  as  to  dampen 
the  wall  paper  or  spoil  the  fresco  decorations.  It  is  also  known  that 
a  house  with  damp  walls  is  unhealthy  and  a  frequent  cause  of  rheu- 
matism ;  besides  this  the  moisture  in  the  brickwork  prevents  the  mor- 
tar, if  made  of  lime,  from  becoming  hard,  and  is  also  liable  to  com- 
municate itself  to  the  woodwork,  thereby  causing  rot. 

A  building  with  damp  walls  will  also  require  the  consumption  of 
very  much  more  coal  in  warming  than  one  with  dry  walls,  as  the 
moisture  must  be  evaporated  before  the  temperature  of  the  walls  can 
be  raised. 

To  overcome  these  objections  to  a  solid  brick  wall,  particularly  in 
residences  and  school  houses,  hollow  or  vaulted  walls  have  been 
much  used,  and  are  earnestly  recommended  by  various  persons. 

Theoretically,  a  hollow  wall  should  prevent  the  passage  of  moist- 
ure through  the  wall,  and  by  providing  an  air  space  in  the  wall,  make 
the  building  much  cooler  in  summer  and  warmer  in  winter. 

In  the  actual  construction  of  the  walls,  however,  there  are  certain 
difficulties  met  with,  which,  to  a  considerable  extent,  offset  the  advan- 
tages, so  that  hollow  walls  are  comparatively  little  used  in  this 
country. 

The  author  believes,  however,  that  their  use  might  be  much 
extended  with  beneficial  results,  especially  for  isolated  buildings. 

To  obtain  the  full  benefit  of  an  air  space  it  should  be  continuous 
throughout  the  wall,  and  the  bond  or  connection  between  the  two 
parts  of  the  wall  should  be  of  such  material  and  of  such  a  shape  that 
the  moisture  which  penetrates  the  outer  portion  cannot  be  conveyed 
to  the  inner  portion. 


BRICKWORK. 


229 


To  provide  a  continuous  air 
space  in  a  wall  penetrated  by 
openings  is  practically  impossi- 
ble, although  it  may  be  quite 
closely  approximated. 

The  objections  commonly 
<>*  f  urged  against  the  vaulted  wall 
are  increased  cost  and  increase 
of  ground  area,  the  latter  being 
an  important  consideration  in 
city  buildings. 

259.  Methods  of  Con- 
struction.— There  are  several 
ways  of  constructing  vaulted 
walls ;  these  differ  principally 
in  the  method  of  bonding  and 
in  the  thickness  of  the  inner 
and  outer  portions  of  the  wall. 

Generally,  at  least  one  por- 
tion of  the  wall  must  be  made  8 
inches     thick    to    sustain    the  • 
weight  of  the  floors,  the  other 
portion    being    only   4    inches 
thick.      Probably    the    thicker 
portion    of    the   wall   is 
more   commonly  placed 
on   the   outside    of    the 
wall,  but  this  necessitates 
extending  the  floor  joist 
through  the  air  space,  and 
thus  to  a  great  extent  neu- 
tralizing the  benefits  de- 
rived from   it.     By  this 
method  the  thicker  por- 
tion of   the  wall  is  still 
subjected  to  the  injuri- 
ous effects  of  the  moist- 
ure. 

For  two-story  build- 
ings the  author  recommends  that  the  walls  be  constructed  as  shown 
in  Fig.  153.  If  the  wall  plate  comes  above  the  attic  joist  the  latter 


Fig-  153- 


230  BUILDING  CONSTRUCTION. 

may  be  supported  on  the  4-inch  wall  if  well  built  of  good  hard  brick. 
If  the  brick  are  not  of  very  good  quality  the  8-inch  wall  should  be 
continued  to  the  upper  joist. 

When  the  bricks,  mortar  and  workmanship  are  of  the  best  quality 
there  is  no  reason  why  this  construction  should  not  answer  for  even 
four  or  five-story  buildings  (if  used  only  for  dwelling  or  lodging  pur- 
poses) by  making  the  inner  portion  8  inches  thick  the  full  height 
and  increasing  the  width  of  the  air  space  to  6  inches. 

For  warehouses  the  bearing  wall  in  the  lower  stories  should  be 
increased  in  thickness. 

A  hollow  wall  of  a  given  number  of  bricks  securely  bonded  is  much 
more  stable  than  a  solid  wall  of  the  same  number  of  bricks,  and  will 
also  withstand  fire  better.  It  requires  much  better  workmanship, 
however,  than  is  generally  bestowed  on  solid  walls,  and  the  mortar, 
particularly  in  the  outer  portion,  must  be  of  the  best  quality,  and 
preferably  of  cement. 

Nearly  all  building  regulations  require  that  at  least  the  same  quan- 
tity of  brick  shall  be  used  in  the  construction  of  a  hollow  wall  as 
would  be  used  if  the  wall  were  built  solid,  and  many  of  them  require 
that  both  portions  of  the  wall  shall  be  at  least  8  inches  thick  if  the 
wall  is  used  as  a  bearing  wall. 

For  heavy  buildings,  with  steel  floor  joist  and  girders,  it  is  better 
to  build  the  outer  wall  of  the  full  thickness  that  would  be  required 
of  a  single  wall,  and  to  make  the  inner  wall  only  4  inches  in  thick- 
ness, to  serve  merely  as  a  furring  and  to  receive  the  plaster.  Where 
fireproof  arches  are  used  for  the  floors  this  inner  wall  might  without 
injury  rest  on  the  floor  arches. 

260.  Bonding  of  Hollow  Walls. — To  secure  proper  strength 
in  the  wall  it  is  necessary  that  the  two  portions  of  the  wall  shall  be 
well  bonded  together,  so  that  neither  may  buckle  or  get  out  of  plumb. 
Until  within  a  few  years  this  bonding  was  usually  accomplished  by 
placing  brick  headers  across  the  air  space,  with  the  ends  slightly 
built  into  the  two  portions  of  the  wall,  as  shown  at  #,  Fig.  154. 

Brick  bonding,  however  neutralizes  much  of  the  benefit  gained  by 
the  air  space,  as  it  permits  of  the  passage  of  moisture  through  the 
wall  wherever  it  is  bonded.  The  moisture  not  only  passes  through 
the  bond  bricks,  but  also  through  the  mortar  droppings  that  invari- 
ably collect  upon  them. 

The  best  method  of  bonding,  and  the  only  one  which  retains  the 
full  benefits  of  the  air  space,  is  by  means  of  metal  ties  provided  with 
a  drip  in  the  centre.  Either  of  the  metal  ties  shown  in  Fig.  154  may 


BRICKWORK. 


be  used.  That  shown  at  b  is  the  "  Morse  "  tie,  which  is  made  of 
different  sizes  of  galvanized  steel  wire  and  from  7  to  16  inches  in 
length.  The  other  ties  are  not  patented,  and  may  be  made  by  any 
blacksmith. 

That  shown  at  e  is  probably  the  best  shape  where  both  walls  are  8 
inches  thick,  as  it  gets  a  firm  hold  on  the  walls  and  is  also  much 
stiffer  than  the  wire  tie.  The  iron  ties  should  either  be  galvanized 
or  dipped  in  hot  asphalt  or  coal  tar. 

If  either  of  the  ties  b,  c  or  d  are  used  they 
should  be  spaced  every  24  inches  in  every 
fourth  course.  The  tie  e,  being  stronger,  need 
be  used  only  in  every  eighth  course. 

261.  Construction  Around  Openings. 
— Wherever  door  or  window  openings  occur 
in  hollow  walls  it  is  necessary  to  build  the 
wall  solid  for  8  inches  at  each  side  of  the 
opening,  and  also  to  carry  the  relieving  arch 
entirely  through  the  wall.  It  is  almost  impos- 
sible to  prevent  some  moisture  passing 
through  the  wall  at  these  points,  but  much 
may  be  done  by  covering  the  top  of  the 
relieving  arch  with  hot  tar  and  laying  the  con- 
necting brickwork  in  cement  mortar.  The 
top  of  the  relieving  arch  is  obviously  the 
most  vulnerable  point,  and  should  be  pro- 
tected in  some  way  and  kept  as  free  as  possi- 
ble from  mortar  droppings. 
Ventilation  of  Air  Space. — There  seems  to  be  some  differ- 
ence of  opinion  as  to  whether  or  not  the  air  space  should  be  con- 
nected with  the  outer  air.  American  writers,  however,  appear  to  be 
generally  of  the  opinion  that  the  air  space  should  be  ventilated  to 
carry  off  the  moisture  that  collects  on  the  inside  of  the  outer  portion 
of  the  wall. 

It  is  recommended  that  the  bottom  of  the  air  space  be  ventilated 
through  openings  into  the  cellar,  and  that  openings  be  left  in  the  inner 
portion  of  the  wall  just  under  the  coping  of  a  parapet  wall,  or  above 
the  attic  floor  joist  if  the  wall  is  covered  by  the  roof.  If  the  air 
space  cannot  be  ventilated  into  the  attic,  then  ventilation  flues  should 
be  carried  up  and  topped  out  like  a  chimney,  or  built  in  connection 
with  a  chimney.  It  is  also  recommended  that  a  U-shaped  drain  tile 


232  BUILDING  CONSTRUCTION. 

be  laid  at  the  bottom  of  the  air  space  to  collect  any  moisture  that 
may  run  down  the  outer  wall. 

262.  Hollow  Walls  with  Brick  Withes.— Brick  walls  are 
sometimes  built  with  a  4-inch  inner  and  outer  facing  connected  with 
solid  brick  withes,  as  shown  in  Fig.  155,  the  air  space  being  made  4, 
8  or  12  inches,  according  to  the  height  and  character  of  the  build- 
ing. Congress  Hall,  Saratoga,  N.  Y.,  a  portion  of  which  is  seven 
stories  high,  is  built  in  the  manner  shown  in  Fig.  155,  and  has  stood 


successfully.  If  such  a  wall  is  built  of  the  quality  of  brick  generally 
made  in  the  New  England  States,  and  with  perfect  workmanship,  it 
should  have  ample  strength  for  any  ordinary  three  or  four-story 
building,  and  would  certainly  be  more  stable  and  conduct  less  heat 
and  moisture  from  and  into  the  building  than  a  solid  wall  of  one- 
half  more  bricks.  With  such  bricks  and  workmanship  as  are  com- 
monly found  in  many  portions  of  the  country,  however,  walls  built 
in  this  way  should  never  be  used  for  any  building  larger  than  a  two- 
story  dwelling.  Theoretically,  the  inside  of  the  wall  opposite  the 
withes  would  be  subject  to  dampness,  but,  of  course,  not  to  as  great 
an  extent  as  with  the  solid  wall. 


BRICKWORK. 


233 


For  two-story '  dwellings,  this  wall,  if  well  constructed  and  the 
withes  securely  bonded  to  the  facings,  should  make  a  much  more 
healthy  and  comfortable  building  than  the  solid  wall. 

263.  Furring    Blocks. — For    office    buildings   furring    blocks 
designed  for  that  especial  purpose  are  often  used  for  lining  or  furring 
the  external  walls,  and  sometimes  hollow  bricks  are  used  for  the  inner 
4  inches  of  a  solid  wall,  but  the  latter  have  not  proved  a  success  in 
excluding  moisture.     The  objection  to  any  kind  of  furring  and  to 
hollow  brick   is  that  there  must   necessarily   be   some   connection 
between  the  material  of  the  lining  or  furring  and  the  wall,  and  this 
connection  allows  of  the  passage  of  heat  and  moisture. 

264.  Brick  Veneer   Construction. — It  is  quite  common  in 
many  sections  of  the  country  to  build  dwellings,  and  even  three  and 


Fig.  156. 

four-story  buildings,  with  the  outer  walls  of  frame  construction  and 
then  to  veneer  the  frame  with  a  4-inch  facing  of  brick,  feuildings 
built  in  this  way  have  the  same  appearance,  both  externally  and 
internally,  as  if  the  walls  were  entirely  of  brick. 

Where  lumber  is  cheap  and  brickwork  comparatively  expensive 
this  method  of  construction  possesses  some  advantages,  although  it 
is  not  generally  approved  by  architects,  and  should  only  be  used 
where  a  hollow  brick  wall  cannot  be  afforded.  The  advantages  pos- 
sessed by  a  brick-veneered  frame  wall  over  a  solid  brick  wall 
are  that  it  costs  less  and  the  air  spaces  prevent  any  possibility  of  the 
passage  of  moisture,  and  also  makes  the  house  much  warmer  in  win- 
ter and  cooler  in  summer. 

About  the  only  advantage  that  it  possesses  over  a  well-built  frame 
building  is  that  it  reduces  the  insurance  rate,  as  the  veneer  offers 
some  protection  from  fire  in  adjoining  buildings.  A  veneered  build- 


234 


BUILDING  CONSTRUCTION. 


ing,  however,  is  not  near  as  safe  from  fire  as  a  brick  building,  and 
would  probably  be  destroyed  by  fire  on  the  inside  about  as  rapidly  as 
though  the  frame  were  covered  with  siding  or  shingles. 

The  only  differences  in  the  planning  of  a  veneered  building  from 
that  of  a  frame  building  are  that  the  walls  are  5  inches  thicker,  the 
foundations  must  project  sufficiently  beyond  the  frame  to  support 
the  veneer,  and  the  elevations  are  drawn 
the  same  as  for  a  brick  building. 

The  wooden  frame  should  be  con- 
structed in  the  best  manner,  with  at 
least  4x6  sills,  4x8  posts,  4x6  girts  and 
4x4  plates,  and  be  well  braced  at  the 
angles.  After  the  frame  is  up  it  should 
be  sheathed  diagonally  and  then  covered 
with  tarred  felt. 

It  is  also  very  impor- 
tant that  the  framing 
timber  shall  be  as  dry  as 
possible,  particularly  the 
sill  and  girts,  and  the 
frame  must  be  perfectly 
plumb  and  straight. 

The  veneer  is  usually 
laid  with  pressed  or  face 
brick,  with  plumb  bond, 
which  should  be  tied  to 
the  wooden  wall  with 
metal  ties.  The  Morse 
tie,  shown  at  a,  Fig.  156, 
is  probably  the  best  for 
this  purpose,  although  the  author  has  used  the  tie  shown  at  b  with 
very  satisfactory  results.  The  ties  should  be  placed  on  every  other 
brick  in  every  fifth  course. 

In  laying  out  the  wall  on  the  floor  plans  6  inches  should  be  allowed 
from  the  outside  of  the  studding  to  the  face  of  the  wall.  This  gives 
an  air  space  of  about  i  inch  between  the  brick  and  sheathing  and 
avoids  chipping  the  bricks  where  the  wooden  wall  is  a  little  full.  It 
is  a  good  idea  to  build  a  2-inch  U-shaped  drain  tile  in  the  founda- 
tion wall  under  the  air  space  to  collect  any  moisture  that  may  pene- 
trate the  veneer.  The  air  space  should  also  be  ventilated  at  the  bot- 
tom through  2-inch  drain  tile,  as  shown  in  Fig.  157. 


pe. 


BRICKWORK. 


235 


The  top  of  the  brickwork  generally  terminates  under  the  eaves  or 
gable  finish.  If  the  building  has  a  flat  roof,  with  parapet  walls,  the 
latter  should  be  coped  with  either  copper  or  galvanized  iron  and 
tinned  on  the  back  down  to  the  flashing. 

Fig.  157  shows  a  partial  section  through  the  foundation  and  a  por- 
tion of  the  first  story  wall  of  a  veneered  dwelling  to  illustrate  the 
construction  described  above. 

DETAILS  OF  CONSTRUCTION  IN  BRICKWORK. 

265.  Brick  Arches. — Brick  arches  are  generally  used  for  span- 
ning the  openings  in  brick  walls,  and  where  there  is  sufficient  height 
for  the  arch  they  form  the  most  durable  support  for  the  wall  above. 
The  arches  should  be  laid  with  great  care  with  full  joints,  and  all 


Fig.  158. 


Fig.  159- 


arches  having  a  span  of  over  10  feet  should  be  laid  in  strong  cement 
mortar,  and  it  is  much  safer  to  lay  all  brick  arches  in  cement. 

Gauged  Arches. — When  arches  are  built  of  common  brick  the 
bricks  are  laid  close  together  on  the  inner  edge,  with  wedge-shaped 
joints,  as  shown  in  Fig.  161,  but  when  built  of  face  bricks  the  arch 
rim  is  laid  out  on  a  floor  and  each  brick  is  cut  and  rubbed  to  fit 
exactly  the  place  chosen  for  it,  so  that  the  radial  joints  are  of  the 
same  thickness  throughout.  Such  work  is  called  gauged  work. 

Bond. — The  only  point  requiring  especial  mention  in  connection 
with  brick  arches  is  the  bond.  When  gauged  arches  are  used  the 
bricks  are  generally  bonded  on  the  face  of  the  arch  to  correspond 
with  the  face  of  the  wall,  as  shown  in  Fig.  158.  Such  an  arch  is 
called  a  bonded  arch.  Bonded  gauged  work  makes  the  neatest  and 
strongest  job,  but  it  is  too  expensive  for  common  brick  arches. 

Arches  of  common  brick  are  generally  built  in  concentric  rings, 
either  without  connection  with  each  other,  except  by  the  tenacity  of 


BUILDING  CONSTRUCTION. 


the  mortar,  or  else  bonded  every  few  feet  with  bondimg  courses  built 
in  at  intervals  like  voussoirs,  as  shown  by  the  heavy  lines  at  A, 
Fig.  1 60.  When  the  concentric  rings  are  all  headers,  as  in  Fig.  159, 
the  arch  is  designated  as  a  rowlock  arch,  or  bond,  and  when  built 
with  bonding  courses,  as  in  Fig.  160,  it  is  known  as  block  in  course 

bond.  Segmental  arches  are 
often  built  with  concentric 
rings  of  stretchers  (Fig.  i6i)> 
which  may  be  bonded  at  right 
angles  to  the  face  by  hoop  iron. 
When  the  radius  is  over  15  feet 
this  should  be  stronger  than 
the  rowlock  bond. 

Common  brick  arches  are 
sometimes  bonded  by  introduc- 
ing headers  so  as  to  unite  two 
half  brick  rings  wherever  the 
joints  of  two  such  rings  happen  to  coincide.  Fig.  162  shows  the 
bonding  employed  in  arching  the  Vosburg  tunnel  on  the  Lehigh  Val- 
ley Railroad,  the  span  being  28  feet.  Building  an  arch  in  concentric 
rings  has  the  objection  that  each  ring  acts  nearly  or  quite  independ- 
ent of  the  other,  and  the  least  settlement  in  the  outer  rings  throws 
the  entire  pressure  on  the  inner 
ring,  which  may  not  be  able  to 
resist  it.  When  bonding  courses 
are  used,  however,  they  serve  to 
tie  the  rings  together  and  to  dis- 
tribute the  pressure  between  them, 
so  that  the  above  objection  is 
overcome.  For  arches  of  wide 
span,  or  when  heavily  loaded, 
some  form  of  block  in  course  bond 
should  be  used.  Hoop  iron  is  often 

built  into  arch  rings  parallel  to  the  soffit,  and  is  also  often  worked  in 
the  radial  joints  to  unite  the  different  rings.  The  stability  of  an  arch 
may  be  greatly  increased  by  its  use. 

Skewback.—lv.  building  brick  arches  of  large  span  it  is  important 
to  have  a  solid  bearing  for  the  arch  to  spring  from.  Such  a  bearing 
may  be  best  obtained  by  using  a  stone  skewback,  as  shown  in 
Figs.  161  and  162.  The  stone  should  be  cut  so  as  to  bond  into 
the  brickwork  of  the  pier,  and  the  springing  surface  should  be  cut  to 


BRICKWORK. 


237 


a  true  plane,  radiating  to  the  centre  from  which  the  arch  is  struck. 
For  large  arches  the  skewbacks  should  be  bedded  in  cement. 

Flat  Arches. — Flat  arches  are  often  built  over  door  or  window 
openings  in  external  walls  for  architectural  effect.  Such  arches,  if 
built  with  a  perfectly  level  soffit, 
almost  always  settle  a  little,  and  it  is 
better  to  give  a  slight  curve  to  the 
soffit,  as  in  Fig.  163,  or  else  support 
the  soffit  of  the  arch  on  an  angle  bar,, 
the  vertical  flange  of  the  bar  being 
concealed  behind  the  arch. 

Relieving  Arches. — The  portion  of 
a  wall  back  of  the  face  brick  arch,  or 
stone  lintel  over  door  or  window 
openings,  should  be  supported  by  a 
rough  brick  arch,  as  shown  in 
Fig.  164.  A  wooden  lintel  is  first  put 
across  the  opening,  and  on  this  a 
brick  core  or  centre  is  built  for  turn- 
ing the  arch.  Sometimes  arched  wooden  lintels  are  used  and  the 
arch  turned  on  them.  When  the  walls  are  plastered  without  furring 
the  method  shown  in  the  figure  is  the  best,  as  there  will  be  less  wood- 
work. The  lintel  should  not  have  a  bearing  on  the  wall  of  more  than 
4  inches,  and  the  arch  should  spring  from  beyond  the  end  of  the  lin- 


Fig.  163. 


Fig.  164 


tel  as  at  Ay  and  not  as  at  -#,  as  in  the  latter  method  the  arch  is 
affected  by  the  shrinkage  of  the  lintel. 

266.  Vaults. — Brick  vaults  are  usually  constructed  in  the  same 
way  as  common  brick  arches,  except  that  the  bricks  should  be 
bonded  lengthwise  of  the  vault. 


238 


BUILDING  CONSTRUCTION. 


Cross,  or  groined  vaults,  are  generally  supported  at  the  inter- 
sections by  diagonal  arches  of  the  proper  curvature,  built  so  as  to 
drop  8  or  12  inches  below  the  soffit  of  the  vault. 

Vaults  may  be  economically  constructed  by  a  combination  of 
brickwork  and  concrete,  or  even  entirely  of  concrete.  When  built 
entirely  of  concrete,  however,  very  strong  centres  are  required. 

Fig.  165*  shows  a  method  of  constructing  vaults  much  used  by 
the  ancient  Romans.  A  light  temporary  centre  of  wood  was  first 
put  in  place,  and  on  this  light  brick  arches  were  built  to  form  a 
framework  for  supporting  the  weight  of  the  vault  until  set.  These 


Fig.  165. 

brick  arches  were  called  armatures,  and  as  they  became  the  real  sup- 
port of  the  vault  only  very  light  wooden  centres  were  required. 
After  the  armatures  were  built  the  spaces  between  them  were  filled 
with  rough  masonry  or  concrete,  as  shown  in  Fig.  166. 

267.  Chimneys. — In  planning  brick  chimneys  the  principal 
points  to  be  considered  are  the  number,  arrangement  and  size  of  the 
flues  and  the  height  of  the  chimney.  Every  fireplace  should  have  a 
separate  flue  extending  to  the  top  of  the  chimney.  Two  or  three 
stoves,  however,  may  be  connected  with  one  flue  if  it  is  of  sufficient 
size,  and  the  kitchen  range  may  be  connected  with  the  furnace  flue 
without  bad  results,  and  often  the  draught  of  the  furnace  will  be  ben- 
efited thereby.  For  ordinary  stoves  and  for  a  small  furnace  an  8x8 

*  Figs.  165  and  166  are  taVen  from  the  Brickbuilder,  by  permission. 


BRICKWORK. 


239 


flue  is  sufficiently  large  if  plastered  smooth  on  the  inside,  but  it  is 
generally  better  to  make  the  furnace  flues  8x12  inches  and  also  the 
fireplace  flues,  except  for  very  small  grates. 

The  best  smoke  flue  is  one  built  of  brick  and  lined  with  fire  clay 
tile,  or  else  a  galvanized  iron  pipe  supported  in  the  middle  of  a  large 
brick  flue.  When  the  latter  arrangement  is  used  the  space  surround- 
ing the  smoke  pipe  may  be  used  for  ventilating  the  adjoining  rooms 
by  simply  putting  registers  in  the  wall  of  the  flue. 

When  galvanized  iron  smoke  pipes  are  used  the  metal  should  be  at 
least  of  No.  20  gauge,  and  No.  16  gauge  for  boiler  flues.  Even  then 


Fig.  i 66. 

the  pipe  is  liable  to  be  eaten  away  by  rust  or  acids  within  ten  or 
twelve  years.  Fire  clay  flue  lining,  on  the  other  hand,  is  imperishable. 

Smoke  flues  are  sometimes  made  only  4  inches  wide.  Such  flues 
may  work  satisfactorily  at  first,  but  they  soon  get  clogged  with  soot 
and  fail  to  draw  well,  and  should  never  be  used  unless  it  is  imprac- 
ticable to  make  the  width  greater. 

More  flues  smoke  or  draw  poorly  on  account  of  the  chimney  not 
being  of  sufficient  height  than  from  any  other  cause.  A  chimney 
should  always  extend  a  little  above  the  highest  point  of  the  build- 
ing or  those  adjacent  to  it,  as  otherwise  eddies  may  be  formed  by 
the  wind  which  may  cause  a  downward  draught  in  the  flue  and 
make  it  smoke.  If  it  is  impracticable  to  carry  the  chimney  above 
the  highest  point  of  the  roof  it  should  be  topped  out  with  a  hood, 


240 


BUILDING  CONSTRUCTION. 


open  on  two  sides,  the  sides  parallel  to  the  roof  being  closed.  The 
walls  and  withes  (or  partitions)  of  a  chimney  should  be  built  with 
great  care,  and  the  joints  carefully  filled  with  mortar  and  the  flues 
plastered  smooth  on  the  inside  with  Portland  cement,  both  to  pre- 
vent sparks  or  air  from  passing  through  the  walls  and  to  increase  the 
draught.  Chimneys  were  formerly 
plastered  with  a  mixture  of  cowdung 
and  lime  mortar,  which  was  called 
pargetting,  but  this  mixture  is  now  sel- 
dom, if  ever,  used.  Portland  cement 
is  not  affected  by  heat  and  is  the  best, 
material  for  this  purpose. 

In  building  the  chimney  more  or 
less  mortar  and  pieces  of  brick  are  sure 
to  drop  into  the  flue,  and  a  hole  should 
be  left  at  the  bottom,  with  a  board 
stuck  in  on  a  slant,  to  catch  the  falling 
mortar.  After  the  chimney  is  topped 
out  the  board  and  mortar  should  be 
removed  and  the  hole  bricked  up.  If 
there  are  bends  in  the  flue,  openings 
should  be  left  in  the  wall  at  those 
points  for  cleaning  out  any  bricks  and 
mortar  that  may  lodge  there.  The 
outer  wall  of  a  chimney  should  be  8 
inches  thick,  unless  a  flue  lining  is 
used,  to  prevent  the  smoke  being 
chilled  too  rapidly. 

During  the  construction  of  the 
building  the  architect  or  superintend- 
ent should  be  careful  to  see  that  no 
woodwork  is  placed  within  i  inch  of 
the  walls  of  a  flue,  and  that  all  the 
flues  are  smoothly  plastered  their 
entire  height. 

The  arrangement  of  the  flues  is  ordinarily  very  simple.  Fig.  167 
shows  the  ordinary  arrangement  of  the  flues  in  a  chimney  containing 
a  furnace  flue  and  fireplaces  in  first  and  second  stories,  and  ash  flue 
for  second  story  fireplace. 

Fig.  1 68,  from  Part  II.  of  "Notes  on  Building  Construction," 
shows  the  arrangement  of  the  flues  in  a  double  chimney,  with  fire- 
places in  five  stories. 


Fig.   i67.-Plan. 


BRICKWORK. 

A  mmm-mm\Q  HORUONTM.  SECTION A.8. 

'Mmmtti 
s 


241 


242 


B  UILDING  CONS  TR  UC  TION. 


268.  Fireplaces. — Rough  Opening. — In  building  fireplaces,  no 
matter  how  they  are  to  be  finished,  it  is  customary  first  to  build  a 
rough  opening  in  the  chimney  from  6  to  8  inches  wider  than  the  in- 
tended width  of  the  finished  opening,  and  an  inch  or  two  higher, 
drawing  in  the  brick  above  to  form  the  flue,  as  shown  in  Figs.  167 
and  1 68.  The  front  wall  of  the  chimney  over  the  opening  may  be 
supported  by  a  segment  arch  when  there  is  sufficient  abutment,  but 
when  the  side  walls  are  but  4  or  8  inches  thick,  heavy  iron  bars 
should  be  used  to  support  the  brickwork.  The  depth  of  the  rough 
opening  should  be  at  least  12  inches,  to 
permit  of  an  8-inch  flue. 

The  bottom    of    the  chimney,   when 
there  are  fireplaces,  is  usually  built  hol- 
low to  form  a  receptacle  for  the  ashes 
from  the  grate,   as  shown  in    Fig.   169. 
If  the  fireplace  is  to  be  used  frequently 
an  ash  pit  is  almost  a  necessity,  espe- 
cially in  residences,  and  should  always 
be  provided  when  practicable.      When 
the  fireplace  is  above  the  ground  floor  a 
flue  can  generally  be  built  to  connect  the 
bottom  of  the  fireplace  with  the  ash  pit. 
In  the  chimney  shown  by  Figs.  167  and 
169  the  ash  flue  is  built 
back   of    the    lower    fire- 
place.    When  there  is  no 
furnace  flue  the  ash  flue 
can   be   carried   down  at 
one  side  of  the  lower  fire- 
place,   thereby   saving    4 
inches  in  the  thickness  of 
the    chimney.      One    ash 


Fig.  169. 


flue  will  answer  for  several  fireplaces.  A  cast  iron  door  and  frame 
(usually  about  10x12  inches)  should  be  built  in  the  bottom  of  the 
ash  pit  to  permit  of  removing  the  ashes. 

The  ash  pit,  rough  opening  and  flues  form  the  chimney,  and  are 
all  built  at  the  same  time  by  the  brick  mason,  who  also  builds  the 
trimmer  arch. 

Trimmer  Arch. — In  buildings  with  wooden  floor  construction  the 
hearth  is  usually  supported  by  a  "trimmer  arch,"  commonly  2  feet 
wide  by  the  width  of  the  chimney,  turned  on  a  wooden  centre  from 


BRICKWORK. 


the  chimney  to  the  header  or  trimmer,  as  shown  in  Fig.  169.  The 
centre  is  put  up  by  the  carpenter,  one  side  being  supported  by  the 
trimmer  and  the  other  by  a  projecting  course  on  the  chimney,  or  by 
flat  irons  driven  into  the  joints.  Although  not  needed  for  support 
after  the  arch  has  set,  the  centre  is  generally  left  in  place  to  afford  a 
nailing  for  the  lath  or  furring  strips  on  the  ceiling  below. 

Sometimes  a  flagstone  is  hung  from  the  joists  to  support  the  hearth, 
but  a  stone  generally  costs  more  than  the  arch,  and  in  the  opinion  of 
the  author  is  not  as  good,  as  the  arch  will  adjust  itself  to  a  slight  set- 
tlement in  the  chimney,  and  is  not  affected  by  shrinkage  of  the  floor 
joists. 

Finished  Fireplace. — After  the  building  is  plastered  the  finished 
fireplace  is  built,  usually  by  the  parties  furnishing  the  material, 
unless  it  is  of  brick,  when  the  work  may  be  done  by  any  skilled 
brick  mason. 

At  the  present  time  the  larger  number  of  fireplaces  are  probably 
built  with  fire  brick  linings  and  tile  facings  and  hearths,  with  wooden 


Mantel    ™e  Facing 
Chimney  Plastered. 


ddtng 


Fig   169*. 


Tile'  ^'Mantel 

Chimney    furred 


mantels,  after  the  manner  shown  by  Figs.  169  and  1690.'  The  various 
steps  in  building  such  a  fireplace  are  to  first  level  up  for  the  hearth 
with  brick  or  concrete,  after  which  the  hearth  and  "  under  fire  "  are 
laid,  the  metal  frame  at  the  edge  of  the  opening  set  up  and  the  lining 
and  the  backing  for  the  tile  facing  built.  After  this  work  is  com- 
pleted the  tile  facing  is  set,  and  when  the  mortar  has  dried  out,  the 
mantel,  if  of  wood,  is  set  against  it.  It  is  best  to  use  glazed  tile  for 
the  hearth  and  facings,  and  they  should  always  be  set  in  rich  Port- 
land cement  mortar.  The  sides  of  the  lining  or  fire  box  should  be 
beveled  about  3  inches  to  the  foot,  and  the  back  should  be  brought 
inward  at  the  top,  as  shown,  so  that  the  opening  into  the  flue  will  be 
only  about  3  inches  wide.  This  opening  is  called  the  "  throat,"  and 
its  proportions  determine  in  a  great  measure  whether  the  draught  will 
be  good  or  bad. 


242/>  BUILDING  CONSTRUCTION. 

A  damper  should  always  be  provided  for  closing  the  throat.  The 
simplest  arrangement  is  a  piece  of  heavy  sheet  iron  with  a  ring  on 
the  edge,  as  shown  at  A,  Fig.  169,  which  may  be  operated  by  the 
poker.  A  much  better  device,  and  one  now  quite  frequently  used, 
consists  of  a  cast  iron  frame  with  a  door  which  may  be  pushed  back 
to  give  the  full  opening,  and  the  door  also  has  a  sliding  damper  suffi- 
cient to  let  off  the  gases  after  the  fire  is  well  started.  This  device 
can  be  obtained  of  most  mantel  dealers,  and  generally  insures  a  good 
draught.  A  small  cast  iron  ash  dump  should  also  be  placed  in  the 
bottom  of  the  fireplace  when  there  is  an  ash  pit. 

Grates. — There  are  a  great  many  styles  of  grates  that  may  be  used 
in  fireplaces.  In  a  fireplace  such  as  has  been  described,  the  "club 
house  "  grate  is  probably  most  frequently  used  in  localities  where  soft 
coal  is  burned.  It  consists  of  a  cast  iron  grate  supported  by  four 
legs,  and  with  an  ornamental  front  about  6  inches  high.  It  has  no 
back  or  sides,  but  should  fit  close  to  the  fire  brick  lining.  There  is 
also  a  movable  front  to  close  the  opening  beneath  the  grate.  Such  a 
grate  works  very  well  for  soft  coal  or  coke. 

For  fireplaces  that  are  to  be  frequently  or  steadily  used  a  narrow 
opening  (say  21  inches)  is  most  desirable,  as  the  wider  openings  are 
very  wasteful  of  coal. 

Fireplaces  in  which  wood  is  to  be  burned  may  have  openings  up  to 
4  feet  wide,  3-foot  openings  being  quite  common.  Wood  is  generally 
burned  on  andirons. 

For  burning  hard  coal,  especially  in  ornamental  fireplaces,  basket 
grates  having  an  open  front  and  solid  back  and  ends  are  often  used. 
They  are  made  of  various  sizes  and  may  be  used  in  any  fireplace. 

One  of  the  most  practical  devices  for  a  fireplace  is  the  portable 
fireplace,  which  is  a  complete  cast  iron  fireplace  with  fire  box,  damp- 
ers, shaking  grate  and  separate  front  piece  for  summer.  It  can  be 
set  in  any  opening  of  suitable  size,  and  is  sure  to  draw  well  if  the  flue 
is  reasonably  large  and  high.  These  fireplaces  are  finished  with  an 
ornamental  frame  about  3  inches  wide,  in  different  finishes,  and  can 
"be  used  with  either  tile,  marble  or  brick  facings.  They  are  made 
with  20  and  24-inch  openings. 

Brick  Fireplaces. — Fireplaces  may  be  built  with  pressed  brick 
facings,  with  either  square  or  arched  openings,  and  a  wool  mantel 
set  against  them,  the  same  as  with  a  tile  facing.  If  wood  is  to  be 
burned  pressed  brick  may  also  be  used  for  the  linings,  but  they  will 
not  withstand  the  intense  heat  of  a  coal  fire.  For  a  coal  fire  fire 
brick  should  be  used  for  the  linings. 


BRICKWORK.  2$2C 

Although  brick  facings  in  connection  with  wooden  mantels  have 
been  much  used,  the  practice  does  not  seem  to  be  very  desirable, 
either  from  a  practical  or  decorative  standpoint.  If  brick  is  to  be 
used  at  all,  it  seems  more  desirable  to  make  the  whole  mantel  of  brick 
or  of  brick  and  terra  cotta.  In  fact  there  are  no  materials  which  can 
be  used  for  finishing  about  a  fireplace  with  better  effect  than  brick  or 


Fig.  1696—  Brick  and  Terra  Cotta  Fireplace  Mantel.     Manufactured  by  Fiske,  Homes  &  Co. 
J.  H.  Ritjhie,  Designer. 

terra  cotta,  although  they  require  artistic  skill  in  the  selection  of  the 
color  and  in  their  arrangement. 

The  great  drawback  in  building  brick  mantels  in  the  past  has  been 
the  difficulty  of  obtaining  bricks  of  suitable  color  and  accuracy,  and 
which  can  be  adapted  to  a  satisfactory  decorative  treatment.  This 
difficulty,  however,  no  longer  exists,  as  there  are  now  two  or  three 


BUILDING  CONSTRUCTION. 

firms  that  make  a  specialty  of  producing  brick  mantels  of  a  high 
grade  of  artistic  value.  These  mantels  are  designed  by  skilled  archi- 
tects to  produce  the  highest  architectural  effect,  and  all  the  parts 


Fig.  i6gc.— Details  of  Buck  Staits. 


are  accurately  fitted,  so  that  the  mantel  can  be  easily  built  by  any 
pressed  brick  mason.  They  are  made  in  a  variety  of  designs  and 
colors,  and  can  be  varied  within  certain  limits  of  size  to  fit  a  particu- 
lar space.  The  mantels  of  the  Philadelphia  and  Boston  Face  Brick 
Co.  have  been  extensively  used  during  the  past  eight  years,  and  with 
very  satisfactory  results 


BRICKWORK. 


242* 


Messrs.  Fiske,  Homes  &  Co.,  of  Boston,  have  also  recently  under- 
taken the  production  of  brick  and  terra  cotta  mantels  of  a  very  high 
degree  of  excellence. 

In  these  mantels  the  ornamentation  is  largely  in  terra  cotta  instead 
of  moulded  bricks,  and  a  special  feature  of  this  terra  cotta  ornamen- 
tation is  that  the  pieces  are  made  in  standard  sizes  which  are  inter- 
changeable. This  feature  will  probably  be  appreciated  and  utilized 
by  architects,  as  it  affords  them  the 
opportunity  of  making  designs  to  suit 
their  own  individual  tastes  as  regards 
the  choice  and  arrangement  of  orna- 
mentation, by  bringing  together  in 
any  desired  combination  the  standard 
interchangeable  pieces,  thus  gaining 
practically  all  the  desirable  features 
of  special  designs,  with  the  additional 
advantages  of  moderate  cost  and  cer- 
tainty of  delivery. 

Fig.  169^  illustrates  a  low-cost  de- 
sign in  which  the  facing  is  made  of 
8xi^-inch  bricks  with  beaded  jambs, 
with  a  bead  and  reel  border,  and  the 
cornice  of  egg  and  dart  and  dentil 
design  ;  a  wood  shelf  and  backboard 
are  used  to  give  a  smooth  and  finished 
effect. 

268f  Brick  Stairs.— For  build- 
ing fireproof  stairs  there  is  probably 
no  better  material  than  brick,  unless 
it  be  Portland  cement  concrete  .in  combination  with  metal  tension 
bars.  Brick  stairs  may  easily  be  built  between  two  brick  walls  by 
springing  a  .segment  arch  from  wall  to  wall  to  form  the  soffit  and 
building  the  steps  on  top  of  this  arch  ;  or,  if  one  side  of  the  stairs 
must  be  open,  that  side  may  be  supported  by  a  steel  I-beam,  as  shown 
in  Fig.  169^,  which  should  be  protected  by  fireproof  tiling.  The1 
stairs  in  the  Pension  Building  at  Washington  were  constructed'  in 
this  way.  The  treads  of  the  steps  may  be  of  hard  pressed  brick,  or 
slate  treads  may  be  laid  on  top  of  the  brick.  Iron  treads  are  not  de- 
sirable, as  they  become  slippery. 

Brick  Spiral  Stairs. — Fig.  169^  shows  a  method  of  con- 
structing spiral  stairs  of  brickwork  commonly  employed  in  Ma- 


Staircase,  House  of  Tristran 
Tours,  France. 


BUILDING  CONSTRUCTION. 


dras,  India.  These  stairs  are  built  without  any  centring,  and  cost  in 
Madras  less  than  one-third  as  much  as  iron  stairs.  It  would  seem 
as  though  this  construction  might  be  advantageously  employed  in 
this  country  where  spiral  stairs  are  to  be  built  in  fireproof  buildings. 
The  dimensions  of  a  typical  Madras  spiral  stair  are  about  as  follows: 

Diameter  of  stair,  wall  to  wall,  inside 6  feet. 

Diameter  of  newel  in  centre I  foot. 

Headway,  from  top  of  step  to  arching  overhead 7  feet  i^  inches. 

Risers,  each 6 

Tread  at  wall *  foot  2  £ 

Tread  at  newel 2| 

Having  determined  the  rise  and  num- 
ber of  steps  in  the  usual  way,  work  is  com- 
menced by  building  up  solid  two  or  three 
steps,  when  the  arch  is  then  started  by  ordi- 
nary terrace  bricks,  5x3x1  inch,  in  lime  mor- 
tar (i|  parts  slaked  lime  to  I  of  clean  river 
sand).  The  bricks  are  put  edgewise  flat 
against  one  another,  with  their  lengths  in 
radii  from  the  centre  of  the  stair,  and  are 
simply  stuck  to  one  another  by  the  aid  of 
the  mortar  without  any  centring.  These 
arch  bricks  are  arranged  as  shown  at  S,  the 
soffit  being  a  continuous  incline,  as  shown 
in  the  section  C  D.  A  slight  rise,  about 
l|-  inch,  is  given  to  the  arch  as  shown  in  the 
section. 

For  forming  the  steps  over  this  arching 
ordinary  bricks  are  used,  usually  9x4^x3 
inches,  trimmed  to  position  and  placed  on 
edge  as  at  T  in  the  plan. 

After  a  reasonable  time  for  the  mortar 
to  harden  the  work  should  bear  a  load  of 
300  pounds  placed-  on  a  step  and  show  no 
sign  of  giving.  With  good  materials  the 
steps  will  bear  much  heavier  loads.— y.  M., 

in  Indian  Engineering. 
"LAN. 

Fig.  ,69*  269;     Brick    Nogging.— Nog- 

ging  is   a   term  that  is   applied   to 

brickwork  filled  in  between  the  studding  of  wooden  partitions.  It  is 
often  employed  in  wooden  partitions  of  dwellings  and  tenement 
houses  to  obstruct  the  passage  of  fire,  sound  and  vermin.  As  no  par- 
ticular weight  comes  upon  the  brick,  and  they  are  not  exposed  to 
moisture,  the  cheapest  kind  of  brick  may  be  used  for  this  purpose. 


BRICKWORK.  243 

The  brick  should  be  laid  in  mortar,  as  in  a  4-inch  wall.  If  the  par- 
tition is  to  be  lathed  with  wooden  laths  it  is  necessary  that  the  width 
of  the  bricks  shall  not  be  quite  equal  to  that  of  the  studding,  to  allow 
for  a  clinch  to  the  plaster.  When  3f-inch  studding  is  used  it  will  be 
necessary  either  to  clip  the  brick  or  lay  them  on  edge. 

When  the  studding  of  a  partition  rests  on  the  cap  of  the  partition 
below  it  is  an  excellent  idea  to  fill  in  the  space  between  the  floor  and 
the  ceiling  below  with  nogging  to  prevent  the  passage  of  fire  and 
mice,  and  two  courses  of  brick  laid  on  horizontal  bridging  is  also  a 
good  means  of  preventing  fire  or  vermin  ascending  in  a  partition. 

270.  Cleaning  Down. — Soon  after  the  walls  are  completed  all 
pressed  or  face  brick  should  be  washed  and  scrubbed  with  muriatic 
acid  and  water,  using  either  a  scrubbing  brush  orcorn  broom.     The 
scrubbing  should  be  continued  until  all  stains  are  removed.     At  the 
same  time  all  open  joints  under  window  sills  and  the  joints  in  the 
stone  and  terra  cotta  work  should  be  pointed,  so  that  when  the  clean- 
ing down  is  completed  the  entire  wall  will  be  in  perfect  condition. 

271.  Efflorescence. — After  a   heavy   driving   storm  of  rain  or 
damp  snow  the  face  of  many  brick  buildings  will  often  be  seen  to  be 
covered  with  a  sort  of  white  efflorescence,  which  greatly  mars  the 
appearance  of  the  brickwork.    This  efflorescence  is  due  either  to  soda 
in  the  bricks,  which  is  drawn  out  by  capillary  attraction  to  the  sur- 
face, where  it  dries  out,  leaving  a  white  deposit,  or  to  pyrites  in  the 
clay,  which  when  burned  gives  rise  to  sulphuric  acid,  which  unites 
with  the  magnesia  in  the  lime  mortar.     In  either  case  the  efflores- 
cence only  appears  after  the  bricks  have  been  thoroughly  saturated 
with  moisture,  either  when  laid  or  by  a  driving  storm,  perhaps  several 
years  after.     According  to  Mr.  Samuel  Cabot  it  is  never  due  to  the 
bricks  alone,  and  seldom  to  the  lime  alone.     It  seems  to  be  impossi- 
ble to  prevent  its  occurrence  except  by  protecting  the  bricks  by  some 
waterproof  or  oily  solution.     After  the  white  appears  on  the  surface 
it  may  be  washed  off  with  clear  water  by  vigorous  scrubbing,  and  if, 
after  the  brickwork  has  become  dry,  a  good  coat  of  boiled  linseed  oil 
is  applied,  it  will  prevent  the  reappearance  of  the  white  until  the  life 
of  the  oil  is  destroyed,  usually  from  three  to  five  years,  when  another 
coat   may  be  applied.     Any  other  preparation  which    renders  the 
bricks  impervious  to  moisture  will  prevent  the  efflorescence. 

272.  Damp-proofing.^-All  brick  and  stone  walls  absorb  more 
or  less  moisture,  and  a  wall  12  inches  thick  may  sometimes  be  soaked 
through  in  a  driving  rainstorm.     In  the  dry  climates  of  Colorado,  Ari- 
zona and  New  Mexico  such  storms  rarely  occur,  and  it  is  customary 

*  See  also  page  403. 


244  BUILDING  CONSTRUCTION. 

in  those  localities  to  plaster  directly  on  the  inside  of  the  walls.  In 
nearly  all  other  portions  of  the  country,  however,  it  is  desirable,  for 
the  sake  of  health  and  economy  in  heating,  if  not  absolutely  neces- 
sary, either  to  furr  or  strip  the  inside  of  solid  walls  with  1x2 -inch 
strips,  or  to  render  the  walls  damp-proof,  either  by  a  coating  of  some 
kind  applied  to  the  outside  of  the  wall,  or  by  building  the  wall  hol- 
low. Furring  the  wall  with  wooden  strips  and  then  lathing  on  them 
prevents  the  moisture  from  coming  through  the  plastering,  but  it 
does  not  prevent  the  wall  itself  from  becoming  soaked,  thereby  neces- 
sitating more  heat  to  warm  the  building  and  gradually  tending  to  the 
destruction  of  the  wall.  The  hollow  wall  is  probably  the  best  device, 
when  properly  built,  for  preventing  the  passage  of  moisture  and  also 
of  heat,  but  in  most  cases  it  is  also  the  most  expensive. 

Brickwork  may  be  rendered  impervious  to  moisture  either  by  paint- 
ing the  outside  of  the  walls  with  white  lead  and  oil  or  by  coating  the 
wall  with  a  preparation  of  paraffine,  or  by  some  of  the  patented 
waterproofing  processes.  The  preparations  containing  paraffine  are 
usually  applied  hot,  and  the  wall  is  also  heated  previous  to  the  appli- 
cation by  a  portable  heater.  They  give  fairly  good  results,  but  are 
quite  expensive,  owing  to  the  time  and  labor  required  for  their  appli- 
cation. 

Sylvester's  process,  which  consists  in  covering  the  surface  of  the 
wall  with  two  washes  or  solutions — one  composed  of  Castile  soap  and 
water  and  one  of  alum  and  water — has  been  used  with  much  success 
for  this  purpose.  A  full  description  of  the  successful  application  of 
this  process  to  the  walls  of  the  gate  houses  of  the  Croton  Reservoir 
in  Central  Park,  New  York,  is  given  in  Baker's  Treatise  on  Masonry 
Construction,  pp.  178-180. 

All  of  these  preparations  change  somewhat  the  color  and  grain  of 
the  brick,  and  are  generally  considered  as  detracting  from  the  appear- 
ance of  the  building. 

Boiled  linseed  oil  is  often  applied  to  brick  walls,  and  two  coats  will 
prevent  the  absorption  of  moisture  for  from  one  to  three  years.  The 
oil  does  not  greatly  change  the  color  of  the  brick,  and  generally 
improves  the  appearance  of  a  wall  which  has  become  stained  or  dis- 
colored in  any  way. 

Common  white  lead  and  oil  paint  is  probably  the  best  material  for 
damp-proofing  external  walls  above  ground,  but  it  entirely  changes 
the  appearance  of  the  building.  Painting  of  new  work  should  be 
deferred  until  the  wall  has  been  finished  at  least  three  months,  and 
three  coats  should  be  given  at  first,  after  which  one  coat  applied 


BRICKWORK.  245 

every  four  or  five  years  will  answer.  A  preparation  known  as  Duresco 
and  made  in  England  has  been  used  in  New  York  and  Chicago  for 
damp-proofing  with  very  satisfactory  results.  In  Chicago  it  was  used 
for  coating  the  inside  of  the  walls  before  the  plastering  was  applied  to 
prevent  the  moisture  penetrating  the  plastering,  which  purpose  it 
seems  to  have  successfully  accomplished. 

Duresco,  when  applied  to  common  or  soft  brick,  not  only  renders 
them  weatherproof,  but  the  color  gives  the  permanent  appearance 
for  which  pressed  brick  are  valued.  It  dries  with  a  hard,  uniform, 
impervious  surface  free  from  gloss,  and  does  not  flake  off  or  change 
color.  It  is  put  up  in  56-pound  kegs,  that  quantity  being  sufficient 
for  covering  1,000  square  feet,  two  coats. 

Cabot" s  Brick  Preservative  (made  in  Boston,  Mass.). — It  is  claimed 
by  the  manufacturer  that  this  preparation  forms  a  thorough  water- 
proofing for  brickwork  and  sandstone,  thus  preventing  the  white 
efflorescence,  the  disintegration  of  chimneys  by  frost,  and  the  growth 
of  fungus. 

It  does  not  change  the  natural  texture  of  the  material  to  which  it 
is  applied  and  leaves  no  gloss.  It  has  been  found  by  actual  experi- 
ment that  one  coat  of  this  preservative  makes  as  good  a  waterproof- 
ing as  three  coats  of  boiled  linseed  oil. 

The  preservative  is  manufactured  in  two  forms  :  colorless,  for  use 
on  any  kind  of  brick  to  render  them  waterproof  and  to  prevent  the 
efflorescence,  and,  with  red  color  added,  to  bring  the  bricks  to  an 
even  shade  without  destroying  the  texture. 

This  material  is  applied  with  a  brush  in  the  same  way  as  oil,  no 
heat  being  necessary.  To  get  the  best  effect  the  brickwork  should 
first  be  washed  down  with  acid  (preferably  nitric  acid)  to  remove 
any  efflorescence  already  formed.  One  gallon  will  cover  about  200 
square  feet  on  the  average  rough  brick  and  a  little  more  on  pressed 
brick.  One  coat  is  generally  sufficient  unless  the  bricks  are 
extremely  soft  and  porous. 

To  prevent  moisture  penetrating  the  top  of  brick  vaults  built 
underground  a  coating  of  asphalt,  from  ^  to  \  of  an  inch  thick  and 
applied  at  a  temperature  of  from  360°  to  518°  F.,  seems  to  give  the 
best  results.  Common  coal  tar  pitch  is  often  used  for  the  purpose, 
but  is  not  as  good  as  asphalt.  If  the  vault  is  to  be  covered  with  soil 
for  vegetation  the  top  course  of  brick  should  be  laid  in  hot  asphalt 
in  addition  to  the  coating. 

273.  Crushing  Strength  of  Brickwork.— In  the  majority  of 
brick  and  stone  buildings  the  crushing  strength  of  brickwork  need 


246  BUILDING  CONSTRUCTION. 

be  considered  only  in  connection  with  piers,  arches  and  under  bearing 
plates  or  templates.  The  strength  of  brickwork  varies  with  the 
strength  of  the  individual  bricks,  the  quality  and  composition  of  the 
mortar,  the  workmanship  and  bond,  and  also  with  the  age  of  the 
brickwork.  It  is  not  the  purpose  here  to  enter  minutely  into  the 
subject  of  the  strength  of  materials,  but  for  general  practice  the  fol- 
lowing safe  loads  may  be  allowed  for  the  crushing  strength  of  brick- 
work in  the  cases  above  mentioned  :  For  New  England  hard-burned 
brick,  in  lime  mortar,  8  to  10  tons  per  square  foot  (112  to  138  pounds 
per  square  inch). 

Same  brick  laid  in  mortar  composed  of  Rosendale  cement  i  part, 
sand  2  parts,  12  tons  per  square  foot  (166  pounds  per  square  inch). 

Same  brick  in  cement  and  lime  mortar,  i  to  3,  14  tons  per  square 
foot  (194  pounds  per  square  inch). 

Same  brick  in  Portland  cement  and  sand  mortar,  i  to  2,  15  tons 
per  square  foot  (200  pounds  per  square  inch). 

Average  hard-burned  Western  brick,  in  Louisville  cement  mortar, 
i  to  2,  10  tons  per  square  foot. 

Same  brick  in  Portland  cement  mortar,  i  to  2,  \2\  tons  per  square 
foot  (175  pounds  per  square  inch). 

It  should  always  be  remembered  that  the  strength  of  brick  piers 
depends  largely  upon  the  thoroughness  with  which  they  are  bonded, 
and  the  building  of  all  piers  should  be  carefully  watched  by  the 
superintendent. 

274.  Measurement  of  Brickwork. — Brickwork  is  generally 
measured  by  the  one  thousand  bricks  laid  in  the  wall.  The  usual 
custom  of  brick  masons  is  to  take  the  outside  superficial  area  of  the 
wall  (so  that  the  corners  are  measured  twice)  and  multiply  by  15  for 
an  8  or  g-inch  wall,  22^  for  a  12  or  1 3-inch  wall  and  30  for  a  16  or 
1 8-inch  wall,  the  result  being  in  bricks.  These  figures  give  about 
the  actual  number  of  bricks  required  to  build  the  wall  in  the  Eastern 
States,  but  in  the  Western  States,  where  the  bricks  are  larger,  they 
give  about  one-third  more  than  the  actual  number  of  bricks  con- 
tained in  the  wall,  and  the  price  is  regulated  accordingly.  During 
the  author's  experience,  in  both  the  Eastern  and  Western  States,  he 
has  never  known  any  deviation  from  these  figures  by  brick  masons. 
In  the  West  two  kinds  of  measurement  are  known,  kiln  count  being 
used  to  designate  the  actual  number  of  bricks  purchased  and  used, 
and  wall  measure,  the  number  of  bricks  there  would  be  on  the  basis 
of  22^  bricks  to  i  superficial  foot  of  1 2-inch  wall. 


BRICKWORK.  247 

In  regard  to  deducting  for  the  openings,  custom  varies  in  different 
localities,  but  unless  the  openings  are  unusually  large  no  deduction  is 
generally  made  for  common  brickwork.  For  measuring  face  brick 
the  superficial  area  of  the  wall  is  taken,  with  the  openings  omitted, 
but  if  the  reveals  of  the  windows  are  more  than  4  inches  they  are 
added  to  the  wall  area.  The  number  of  brick  to  the  superficial  foot 
depends  upon  the  size  of  the  brick  used,  seven  and  one-half  being 
the  average  number. 

Hollow  walls  are  often  measured  the  same  as  solid  walls  of  the 
same  thickness.  Chimneys  with  8x8  or  8x12  flues  are  generally 
measured  as  solid. 

Where  stone  trimmings,  such  as  caps,  sills,  quoins  and  occasional 
belt  courses  are  used,  if  the  brick  mason  sets  the  stone  no  deduction 
is  usually  made  for  face  brick,  but  if  it  is  set  by  another  contractor 
an  allowance  is  sometimes  made  for  the  face  brick  displaced  by  the 
stone. 

As  custom  varies  considerably  in  the  measurement  of  brickwork, 
when  the  work  is  done  by  measurement  the  contract  should  distinctly 
state  how  the  work  is  to  be  measured  and  if  deductions  are  to  be 
made  for  the  openings  and  stonework.  Some  builders  reduce  all  the 
brickwork  to  cubic  feet  and  estimate  the  cost  in  that  way  for  com- 
mon brickwork. 

275.  Superintendence  of  Brickwork. — The  various  portions 
of  the  work  that  require  especial  superintendence  have  been  men- 
tioned in  describing  the  manner  of  doing  the  work.  In  general  the 
points  in  which  brickwork  is  most  commonly  slighted  are  in  wetting 
and  laying  the  brick.  The  importance  of  wetting  the  brick  is  fully 
set  forth  in  Section  238.  In  the  laying  of  the  brick  it  is  often  diffi- 
cult to  get  the  mason  to  use  sufficient  mortar  to  thoroughly  fill  all 
the  joints  and  to  shove  the  bricks.  The  quality  of  the  mortar  should 
also  be  frequently  examined,  as  brick  masons  in  some  localities  like 
to  mix  a  little  loam  with  the  sand  to  make  the  mortar  "work  well." 

The  bonding  of  the  walls  should  be  watched  to  see  that  the  bond 
courses  are  used  as  often  as  specified.  The  bonding  of  piers  should 
be  particularly  looked  after.  The  laying  of  the  face  brick  and  orna- 
mental features  requires  more  skill,  but  is  not  so  apt  to  be  slighted  as 
the  back  of  the  wall. 

The  superintendent  should  also  see  that  the  dimensions  of  the 
building  are  properly  followed,  openings  left  in  their  proper  places, 
and  the  courses  kept  level  and  the  wall  plumb. 


248  BUILDING  CONSTRUCTION. 

In  very  high  stories,  particularly  in  halls  and  churches,  the 
walls  should  be  stayed  with  temporary  braces  until  the  permanent 
timbers  can  be  built  in.  It  is  also  important  to  see  that  all  bearing 
plates  are  well  bedded,  and  that  all  floor  anchors,  etc.,  are  securely 
built  in  ;  also  to  see  that  all  recesses  for  pipes,  etc.,  marked  on  the 
plans  are  left  in  the  proper  places,  and  that  all  smoke  and  vent  flues 
are  smoothly  plastered. 


CHAPTER  VIII. 
ARCHITECTURAL  TERRA  COTTA. 


276.  Composition  and  Manufacture. — Terra  cotta  is  com- 
posed of  practically  the  same  material  as  bricks,  and  its  characteris- 
tics, as  far  as  the  material  is  concerned,  are  the  same.  Terra  cotta, 
however,  requires  for  its  successful  production  a  much  better  quality 
of  clay  than  is  generally  used  for  bricks,  while  the  process  of  manu- 
facture is  entirely  different. 

The  first  consideration  in  the  manufacture  of  terra  cotta  is  the 
selection  of  the  material.  No  one  locality  gives  all  the  clay  required 
for  first-class  material,  and  each  shade  and  tint  of  terra  cotta  requires 
the  mingling  of  certain  clays  from  different  localities  to  regulate  the 
color. 

A  great  variety  of  excellent  clays  are  mined  in  Northern  and  Cen- 
tral New  Jersey,  large  quantities  being  marketed  annually  for  making 
terra  cotta,  as  well  as  for  fire  bricks,  pottery,  tiles,  etc.  The  color 
varies  from  light  cream  to  a  dark  red. 

A  partial  vitrification  of  the  mass  is  also  desirable  in  the  produc- 
tion of  terra  cotta,  as  it  enhances  the  durability  of  the  body.  To 
achieve  this,  different  materials  are  added  which  tend  to  fuse  the 
body  to  a  harder  consistency.  The  vitrifying  ingredients  usually 
added  to  the  terra  cotta  clays  are  pure  white  sand,  old  pottery  and 
fire  bricks  finely  pulverized,  and  clay  previously  burned,  termed 
"grog." 

The  clay  after  being  mined  must  be  properly  seasoned  before  being 
delivered  at  the  factory.  After  being  received  the  clay  is  crushed 
and  ground,  or  washed,  then  mixed  with  grit,  "grog"  and  water. 
The  clay  is  then  piled  in  layers,  each  quality  being  in  a  separate 
layer  or  stratum.  As  many  as  ten  or  twelve  strata  or  layers  are  piled 
together,  and  from  this  mass  perpendicular  cuts  are  taken,  and  the 
whole  is  again  thoroughly  tempered  in  a  pug  mill,  or  between  rollers. 

After  passing  through  the  machinery,  which  thoroughly  mixes  all 
the  ingredients,  the  plastic  mass  is  moulded  into  small  cakes  for  con- 
venience in  handling  and  sent  up  to  the  moulding  rooms. 

If  several  pieces  of  terra  cotta  of  the  same  size  and  shape  are 
required,  a  full  size  model  of  plaster  and  clay  is  first  made,  and  from 


25o  BUILDING  CONSTRUCTION. 

this  a  plaster  mould  is  taken.  In  the  making  of  these  models  and 
moulds  the  highest  grade  of  skilled  labor  is  required.  When  the. 
moulds  are  dry  they  are  sent  to  the  pressing  department  ;  here  the 
plastic  clay  is  pressed  into  the  moulds  by  hand,  and  when  partially 
dry  the  work  is  turned  out  on  the  floor.  The  ware  is  then  ready  for 
the  carver  or  modeler,  if  it  is  decorative  work  that  requires  the  use 
of  their  tools,  or  for  the  clay  finisher  if  it  only  requires  undercutting 
or  some  special  work  to  make  it  fit  in  with  other  work. 

The  work  is  then  carefully  dried  on  the  drying  floor,  when  it  is 
ready  to  be  put  into  the  kilns,  where  it  must  remain  seven  days  for 
burning  and  cooling  before  it  is  ready  for  use.  The  kilns  commonly 
used  for  burning  terra  cotta  are  of  the  beehive,  down-draft  pat- 
tern. In  burning  terra  cotta  the  alkaline  salts  contained  in  the  clays 
yield  an  efflorescence,  which,  acting  upon  the  silicates  of  the  surface, 
vitrify  to  a  greater  degree  the  exterior  of  the  terra  cotta,  and  this 
harder  face  should  remain  intact  and  under  no  avoidable  circum- 
stances be  allowed  to  be  chipped,  chiseled  or  broken,  although  the 
joints  sometimes  require  chiseling  or  trimming  to  ensure  a  close  fit. 

If  only  a  single  piece  of  terra  cotta  is  to  be  made,  or  where  no  rep- 
etition is  intended,  no  moulds  are  used,  the  clay  being  modeled 
directly  into  the  required  shape.  The  finished  product  thus  bears 
directly  the  impress  of  the  modeling  artist.  It  can  be  studied, 
improved  or  modified,  and,  when  entirely  satisfactory,  burnt.  On  this 
account  terra  cotta  possesses,  for  highly  decorative  work,  an  advan- 
tage over  all  other  building  materials. 

Terra  cotta  is  usually  made  in  blocks  about  18  inches  long,  6  to  12 
inches  deep  and  of  a  height  determined  by  the  character  of  the  work. 
To  save  material  and  prevent  warping  the  blocks  are  formed  of  an. 
outer  shell,  connected  and  braced  by  partitions  about  i  inch  thick. 
The  partitions  should  be  arranged  so  that  the  spaces  shall  not  exceed 
6  inches,  and  should  have  numerous  holes  in  them  to  form  a  clinch 
for  the  mortar  and  brickwork  used  for  filling. 

277-  Color. — The  color  of  terra  cotta  ranges  from  white  to  a  deep 
red,  according  to  the  chemical  constituents  of  the  clays  used. 

Within  the  past  ten  years  a  great  impetus  has  been  given  to  the 
production  of  special  colors  in  architectural  clay  products.  In  1885 
fully  four-fifths  of  the  terra  cotta  produced  in  the  United  States  was 
red  ;  now  hardly  one-fifth  is  of  that  color.  Buffs  and  grays  of  sev- 
eral shades,  white  and  cream-white  and  the  richer  and  warmer  colors 
•of  the  fire- flashed  old  gold  and  mottled  are  now  the  prevailing  colors. 


ARCHITECTURAL   TERRA  COTTA  251 

By  the  use  of  chemicals  almost  any  required  tone  or  color  may  be 
obtained.  As  a  rule,  however,  it  is  safer,  and  a  better  quality  of 
material  is  likely  to  be  obtained,  by  using  only  those  colors  which  are 
natural  to  the  clay.  A  color  which  necessitates  underburning  or 
everburning  of  the  clay  should  not  be  used. 

If  any  particular  color,  not  natural  to  the  material,  is  desired  the 
architact  should  consult  with  the  manufacturer  in  regard  to  its  effect 
upon  the  durability  and  quality  of  the  finished  product. 

278.  Use. — The  modern  employments  for  terra  cotta,  architec- 
turally,   are  for    tiles,  panels    and    medallions  ;    pilasters,    columns, 
capitals  and  bases  ;  sills,  jambs,  mullions  and  lintels  ;  skewbacks  or 
springers,  arches  and  keys  ;  spandrels,  pediments  and  tympanums  ;. 
mouldings,  belt  courses,  friezes  and  cornices  ;  coping,  chimney  tops, 
cresting,  finials  and  terminals. 

Terra  cotta  is  also  employed  for  brackets,  consoles,  gargoyles,  cor- 
bels, oriel  and  tracery  windows,  and  for  interior  use  for  altars,  bap- 
tismal fonts,  balusters,  newels,  pedestals,  statues,  niches,  mantels,  fire- 
place facings,  and  in  fireproof  buildings  foi  base  mouldings  and  base 
panels,  and  also  in  plain  blocks  for  ashlar. 

Terra  cotta  is  also  suitable  for  all  kinds  of  garden  decorations, 
such  as  balustrades,  ferndelabras,  flower  baskets  and  vases  and  other 
horticultural  appliances. 

279.  Durability.— The  principal  value  of  terra  cotta  lies  in  its 
durability.     When  made  of  the  right  material  and  properly  burned  it 
is  impervious  to  wet,  or  nearly  so,  and  hence  is  not  subject  to  the  dis- 
integrating action  of  frost,  which  is  a  powerful  agent  in  the  destruc- 
tion of  stone  ;  neither  does  it  vegetate,  as  is  the  case  with  many 
stones.      The  ordinary  acid  gases  contained  in  the  atmosphere  of 
cities  have   no  effect  upon  it,  and  the  dust  which  gathers  on  the 
mouldings,    etc.,  is  washed  away  by  every  rainfall.     Underburned 
terra  cotta  does  not  possess  these  qualities  in  so  great  a  degree,  as  it 
is  more  or  less  absorbent.     Another  great  advantage  possessed  by 
terra  cotta  is  its  resistance  to  heat,  which  makes  it  the  most  desirable 
material  for  the  trimmings  and  ornamental  work  in  the  walls  of  fire- 
proof buildings.     Although  terra  cotta  has  been  used  in  this  country 
for  but  a  comparatively  short  time,  it  has  thus  far  proved"  very  satis- 
factory, and  the  characteristics  above  indicated  would  point  to  its 
being,  in  common  with  the  better  qualities  of  brick,  the  most  durable 
of  all  building  materials. 

In  Europe  there  are  numerous  examples  of  architectural  terra 
cotta  which  have  been  exposed  to  the  weather  for  three  or  four 


252 


BUILDING  CONSTRUCTION'. 


centuries  and  are  still  in  good  condition,  while  stonework  subjected 
to  the  same  conditions  is  more  or  less  worn  and  decayed. 

280.  Inspection. — A  sharp  metallic,  bell-like  ring  and  a  clean, 
close  fracture  are  good  proof  of  homogeneousness,  compactness  and 

(  strength.       Precision    of    the 

^^^^P"^^...  Yfc^S^L     forms  is  in  the  highest  degree 

essential,  and  can  result  only 
from  homogeneous  material 
and  a  thorough  and  experi- 
enced knowledge  of  firing. 

No  spalled,  chipped,  glazed 
or  warped  pieces  of  terra  cotta 
should  be  accepted,  and  the 
pieces  should  be  so  hard  as  to  resist  scratching 
with  the  point  of  a  knife.     The  blocks  should 
also   be   of    uniform   color,   and    all    mouldings 
should  come  together  perfectly  at  the  joints. 

281.  Laying  Out. — It  is  impracticable, 
though  not  impossible,  to  make  terra  cotta  in 
blocks  exceeding  3  feet  by  4  feet  by  18  inches, 
and  when  the  pieces  exceed  this  size  the  cost  is 
greatly  increased.  The  Boston  Terra  Cotta 
Works  have  produced  a  column  and  capital  of 
the  Corinthian  order,  in  white  terra  cotta,  that 
was  14  feet  6  inches  in  height,  the  shaft  being  in 
one  piece  12  feet  long;  but  such  large  pieces 
require  great  skill  and  care  in  the  manufacture 
and  burning  to  prevent  warping,  and  are  very 
expensive.  As  a  rule  it  is  impracticable  to  span 
an  opening  of  any  considerable  length  in  one 
block,  and  even  window  sills  are  generally  made 
in  pieces  about  18  inches  long.  Jamb  blocks 
should  not  exceed  i  foot  in  height  or  there- 
abouts. Mullions,  transoms  and  tracery  should 
be  made  in  as  many  pieces  as  the  design  will  admit,  and  if  there 
are  several  members  in  the  depths  of  the  mouldings  they  should  be  as 
much  divided  as  possible,  care  being  taken  that  each  alternate  course 
bonds  well  upon  the  other.  The  strings  and  cornices  should  be 
divided  into  as  short  lengths  (18  inches  to  2  feet)  as  convenient. 

The  architect  should  show  the  jointing  of  the  terra  cotta  on  his 
drawings,    the   joints   being   arranged    to    conform  with  the  above 


Fig.  170. 


ARCHITECTURAL   TERRA  COTTA. 


253 


requirements,  and  the  work  should  also  be  designed  so  as  to  form  a 
part  of  the  construction  and  to  idapt  itself  as  far  as  possible  to  being 
divided  into  small  pieces.  When  used  for  trimmings  in  connection 


Fig.  171. 

with  brickwork  it  is  very  essential  that  the  pieces  shall  be  of  the 
exact  height  to  bond  in  with  the  courses  of  brick,  and  a  small  piece 
of  brickwork  should  be  built  up,  to  get  the  exact  heights,  before  the 
final  drawings  for  terra  cotta  are  sent  to  the  man- 
ufacturers. All  horizontal  joints  should  be  pro- 
portioned so  as  to  be  equal  to  about  one-fourth 
the  height  of  the  joints  in  the  adjoining  face 
brickwork.  For  elaborate  work  it  is  generally 
necessary  to  consult  with  the  manufacturers  in 
regard  to  the  best  disposition  of  the  joints. 

282.  Examples  of  Construction. — As  an 
example  of  the  jointing  of  jambs  and  lintels, 
Fig.  170,  which  is  from  the  Volta  Building, 
Messrs.  Peabody  &  Stearns,  architects,  is  given. 

Window  sills,  when  made  of   several  pieces, 
should  have  roll  joints  as  shown  in 
Fig.   171,  which  should  terminate 
tinder   the  wood  sills  rather  than 
against  the  edge. 

Cornices. — Where  buildings  are 
trimmed  with  terra  cotta  the  cor- 
nice is  generally  made  of  the  same 
material.  For  cornices  having 
considerable  projection  terra  cotta 
possesses  the  advantages  over  stone 
of  being  much  lighter,  thus  permit- 
ting of  lighter  walls,  and  in  most 


Fig.  172. 


cases  much  cheaper.  With  stone  cornices  it  is  necessary  that  the 
various  pieces  be  of  sufficient  depth  to  balance  on  the  wall.  With 
terra  cotta  cornices,  however,  this  is  not  customary,  the  various  pieces 


254 


BUILDING  CONSTRUCTION. 


being  made  to  build  into  the  wall  only  from  8  to  12  inches  and  being 
supported  by  ironwork.  When  modillions  are  used  they  may  gener- 
ally be  made  to  support  the  construction,  as  shown  in  Figs.  172 
and  173. 

Generally  small  steel  I  or  T-beams  are  used  for  supporting  the  pro- 
jecting members,  and  where  the  projection  is  so  great  as  to  overbalance 
the  weight  of  the  masonry  on  the  built-in  end,  allowing  for  the  weight 
of  snow  on  the  projection,  the  inner  end  of  the  beam  must  be 
anchored  down  by  rods,  carried  down  into  the  wall  until  the  weight 

of  the  masonry  above  the 
anchor  is  ample  to  counteract 
the  leverage  of  the  projection. 
Unless  the  wall  is  very  heavy  it 
is  also  advisable  to  anchor  the 
top  of  the  wall  to  the  roof  tim- 
bers to  prevent  its  inclining 
outward. 

Figs.  172  and  173  *  show  sec- 
tions of  terra  cotta  cornices 
that  have  actually  been  erected 
and  the  manner  in  which  they 
are  supported. 

Fig.  174  shows  a  section  of 
the  cornice  on  the  Equitable 
Life  Insurance  Co.'s  Building, 
in  Denver,  Col. 

These  sections  may  be  taken 

Fig.  i73.  as    models    of    good   and   eco- 

nomical   construction    in   terra 
cotta  where  a  heavy  projection  is  required. 

When  a  cornice  is  to  be  supported  by  ironwork  the  method  of 
anchoring  must  be  decided  on  before  the  work  is  made,  as  provision 
must  be  made  in  making  the  blocks  for  inserting  the  beams  or 
anchors.  Generally  the  beams  are  placed  in  the  joints  in  a  slot 
made  for  the  purpose.  A  copy  of  the  detail  drawings  should  be  fur- 
nished the  contractor  for  the  ironwork,  to  enable  him  to  get  out  his 
part  of  the  work  correctly.  For  other  examples,  see  Section  287$. 
283.  Setting  and  Pointing.— Setting.— Terra  cotta  should 
always  be  set  in  either  the  natural  (such  as  Rosendale  or  Utica) 
cements,  or  in  Portland  cement,  mixed  with  sand,  in  about  the  same 

»  From  the  Clay  Worker,  by  permission. 


ARCHITECTURAL  TERRA  COTTA. 


255 


way  as  stone  is  set.  As  soon  as  set  the  outside  of  the  joints  should 
be  raked  out  to  a  depth  of  f  of  an  inch  to  allow  for  pointing  and  to 
prevent  chipping.  The  terra  cotta  should  be  built  up  in  advance  of 
the  backing,  one  course  at  a  time,  and  all  the  voids  should  be  filled 


Fig.  174. 


with  mortar,  into  which  bricks  should  be  forced  to  make  the  work  as 
solid  as  possible.  All  blocks  not  solidly  built  into  the  walls  should 
be  anchored  with  galvanized  iron  clamps,  the  same  as  described  for 
stonework,  and,  as  a  rule,  all  projecting  members  over  6  inches  in 
height  should  be  anchored  in  this  way. 


256  BUILDING  CONSTRUCTION. 

Terra  cotta  work  is  generally  set  by  the  brick  mason,  but  the  spec- 
ifications should  distinctly  state  who  is  to  do  the  setting  and  pointing. 

Pointing. — After  the  walls  are  up  the  joints  should  be  pointed  with 
Portland  cement  colored  with  a  mineral  pigment  to  correspond  with 
the  color  of  the  terra  cotta.  The  pointing  is  done  in  the  same  way 
as  described  for  stone,  except  that  the  horizontal  joints  in  all  sills, 
and  washes  of  belt  courses  and  cornices,  unless  covered  with  a  roll, 
should  be  raked  out  about  2  inches  deep  and  caulked  with  oakum 
for  about  i  inch  and  then  filled  with  an  elastic  cement 

284.  Time. — One  of  the  principal  objections  to  the  use  of  terra 
cotta  is  the  time  required  to  obtain  it,  especially  when  the  building  is 
some  distance  from  the  manufactory.     Some  six  weeks  are  required 
for  the  production  of  terra  cotta  of  the  ordinary  kind,  and  the  archi- 
tect should  see  that  all  the  drawings  for  the  terra  cotta  work  are 
completed  and  delivered  to  the  maker  at  as  early  a  stage  in  the  work 
as  possible,  so  that  he  may  have  ample  time  to  produce  it. 

Small  pieces  of  terra  cotta  may  sometimes  be  obtained  within  two 
weeks  from  the  receipt  of  the  order  when  the  moulds  are  already  on 
hand.  It  is  always  more  expensive,  however,  to  attempt  to  turn  out 
work  in  such  short  order,  and  inexpedient  on  account  of  the  risks  in 
forcing  the  drying. 

285.  Cost. — A  single  piece  of  terra  cotta,  or  plain  caps  and  sills, 
costs  about  the  same  as  freestone,  when  the  rough  stone  can  be 
delivered  at  a  price  not  exceeding  ninety  cents  per  cubic  foot.    When 
a  number  of  pieces  exactly  alike  are  required,  however,  it  can  be 
produced  in  terra  cotta  cheaper  than  in  stone,  unless  the  terra  cotta 
has  to  be  transported  at  a  large  cost  for  freight.     The  advantage  in 
point  of  cost  in  favor  of  terra  cotta  is  greatly  increased  if  there  is  a 
large  proportion  of  moulded  work,  and  especially  if  the  mouldings 
are  enriched,  or  if  there  are  a  number  of  ornamental  panels,  carved 
capitals,  etc.     It  should  always  be  remembered  that  if  economy  is 
desired  it  can  best  be  obtained  by  a  repetition  of  the  ornamental  fea- 
tures, so  as  to  require  as  few  different  models  as  possible.     When 
stock  patterns  can  be  used  the  cost  is  also  considerably  less  than  when 
the  work  has  to  be  made  from  special  designs. 

The  use  of  terra  cotta  for  trimmings,  and  especially  for  heavy  cor- 
nices, in  place  of  stone,  often  reduces  the  cost  of  the  walls  and  foun- 
dations, as  the  weight  of  the  terra  cotta  will  be  much  less  than  that 
of  stone,  and  the  walls  and  foundations  may  be  made  lighter  in  con- 
sequence. 


ARCHITECTURAL   TERRA  COTTA.  257 

286.  Weight  and  Strength.— The  weight   of   terra   cotta  in 
solid  blocks  averages  122  pounds  per  cubic  foot.     When  made  in  hol- 
low blocks  \\  inches  thick  the  weight  varies  from  65  to  85  pounds 
per  cubic  foot,  the  smaller  pieces  weighing  the  most.     For  pieces 
12x18  inches  or  larger  on  the  face,  70  pounds  per  cubic  foot  should 
be  a  fair  average. 

The  crushing  strength  of  terra  cotta  blocks  in  2 -inch  cubes  varies 
from  5,000  to  7,000  pounds  per  square  inch. 

Hollow  blocks  of  terra  cotta,  unfilled,  have  sustained  186  tons  per 
square  foot  on  blocks  i  foot  high. 

From  these  and  other  tests  the  author  would  place  the  safe  work- 
ing strength  of  terra  cotta  blocks  in  the  wall  at  5  tons  per  square  foot 
when  unfilled  and  10  tons  per  square  foot  when  filled  solid  with  brick- 
work or  concrete. 

If  it  is  desired  to  test  the  strength  of  special  pieces,  two  or  three 
small  pieces  should  be  broken  from  the  blocks  and  ground  to  i-inch 
cubes,  and  then  tested  in  a  machine.  Should  the  average  results  fall 
much  below  6,000  pounds  the  material  should  be  rejected. 

Transverse  Strength  of  Modillions. — A  cornice  modillion  measur- 
ing n£  inches  high  and  8  inches  wide  at  the  wall  line,  with  a  projec- 
tion of  2  feet,  carried  a  load  of  4,083  pounds  without  injury.  A 
similar  modillion  5!  inches  -high,  6  inches  wide,  with  a  projection  of 
14  inches,  broke  under  2,650  pounds.  Another  bracket  from  the 
same  mould,  inserted  in  the  same  hole,  sustained  2,400  pounds  with- 
out breaking. 

287.  Protection. — The  carpenter's  specifications  should  provide 
for  boxing  all  moulded  and  ornamental  work  with  rough  pine  boards 
to  guard  against  damage  during  construction.     Hemlock  is  unsuited 
for  this  purpose,  as  it  is  liable  to  stain  the  terra  cotta. 

287^.  Other  Examples  of  Terra  Cotta  Construction. — 
Many  excellent  illustrations  of  terra  cotta  construction  have  been 
contributed  to  the  Brickbuilder  during  the  past  two  years  (1897—98), 
by  Mr.  Thomas  Cusack,  which  are  accompanied  by  a  great  amount 
of  practical  information  and  advice  regarding  the  subjects  treated. 

Through  the  courtesy  of  Mr.  Cusack  and  the  publishers,  we  are 
enabled  to  reprint  two  illustrations,  Figs.  1740  and  b,  showing  the 
best  construction  of  a  balcony  and  of  parapet  balustrading. 

Fig.  1740  illustrates  the  design  of  a  conventional  balcony,  such  as 
might  be  projected  from  a  second  or  third  story  window  by  way  of 
embellishment.  The  manner  in  which  it  was  constructed  is  shown 
by  the  section  below  the  elevation.  The  objections  to  this  construe- 


BUILDING  CONSTRUCTION. 

tion,  briefly  stated,  are  :  i.  "  The  cantilevers  have  a  strength  out  of 
all  proportion  to  the  load  that  could  by  any  possibility  be  put  upon 
them."  2.  "They  are  placed  about  7  inches  too  high,  cutting 
through  the  top  bed  of  the  modillions  and  into  the  bottom  cf  the 
platform,  thereby  causing  an  incurable  weakness  in  both."  3.  "  The 


inverted  tee  resting  upon  them  is  not  only  quite  unnecessary,  but 
positively  suicidal,  so  far  as  the  terra  cotta  is  concerned."  A  plan, 
such  as  is  shown  in  sections  A  A,  BB,  and  CC,  would  have  been  much 
simpler,  less  expensive  and  avoided  the  objections  above  noted. 


ARCHITECTURAL  TERRA  COTTA. 


257^ 


4"-  S.lfc.  CHArtrtEL 


TERRA  COTTA 
CORrtlCE.  AMD 

BALUSTRADE. 


Fig.  1746. 


BUILDING  CONSTRUCTION. 

"  The  modillion  in  this  case  would  be  made  with  four  walls  and 
one  horizontal  partition,  forming  two  open  chambers  as  at  CC.  Into 
the  upper  one  of  these  we  would  insert  a  3^  by  5-inch  I-beam,  the 
end  of  which  would  be  attached  to  floor  beam,  and  the  surrounding 
space  filled  with  concrete,  as  at  BB.  In  this  way  we  would  get  the 
full  strength  of  the  cantilever  cased  in  cement,  without  weakening 
the  modillions  by  needlessly  cutting  through  its  outer  shell.  The 
platform  would  be  made  in  three  complete  blocks  of  moderate  size, 
two  of  them  resting  directly  on  the  brackets,  the  centre  block  joggle- 
jointed  on  two  sides  with  a  third  side  built  into  the  wall." 

A  balcony  constructed  in  this  way  would  have  a  strength  many 
times  in  excess  of  any  weight  ever  likely  to  be  placed  upon  it. 

Fig.  174^  shows  the  construction  of  the  terra  cotta  cornice  and 
parapet  of  a  residence  at  Madison  Avenue  and  Thirty-ninth  Street, 
New  York,  which  may  be  taken  as  the  typical  construction  of  such 
work. 

The  balusters  are  made  in  three  pieces,  for  the  reasons  that  balus- 
sters  made  in  one  piece  are  subject  to  cleaving  where  the  halves  are 
united,  and  are  very  liable  to  twist  in  the  kiln,  besides  being  more 
expensive  in  the  first  instance  with  no  compensating  advantages.  If 
the  cornice  were  much  broken  by  piers  or  angles,  the  diagonal 
stays  to  roof  might  be  omitted. 


CHAPTER  IX. 
FIREPROOFING 


288.  Most  of  the  materials  employed  for  protecting  the  structural 
portions  of  buildings  from  fire  and  heat,  and  for  filling  between  the 
floor  beams  and  rafters,  are  of  earthy  composition  and  come  within 
the  province  of  the  mason  or  plasterer. 

The  constructive  fireproof  materials — /.  e.,  those  which  have  to 
support  any  weight — most  extensively  used  in  this  country  are  : 
dense,  hollow  tiles,  porous  terra  cotta  tiles  or  blocks  and  various  con- 
crete compositions,  generally  combined  with  steel  in  the  shape  of 
small  bars,  wires  or  netting.  These  materials  are  used  in  different 
shapes  and  in  different  ways,  both  of  which  are,  as  a  rule,  covered 
by  patents  controlled  by  large  manufacturing  corporations.  Most  of 
these  manufacturing  corporations  also  take  contracts  to  furnish  all 
the  fireproofing  material  required  in  the  building  and  to  put  it  in 
place,  leaving  the  building  ready  for  the  plasterer  and  carpenter.  A 
few  manufacturers,  however,  prefer  to  confine  their  business  to  man- 
ufacturing the  material,  and  of  late  years  the  practice  has  become 
quite  general,  especially  in  the  East,  for  the  owner  or  general  con- 
tractor to  buy  tiles  and  the  mason  contractor  on  the  job  to  build 
them  in  place  in  the  building. 

While  with  contractors  of  large  experience  this  practice  has  worked 
very  well,  it  will  generally  be  found  more  satisfactory  to  the  archi- 
tect to  have  the  party  that  furnishes  the  material  put  it  in  place,  as 
the  responsibility  for  the  proper  and  prompt  execution  of  the  work  is 
then  undivided.  If  the  putting  in  place  of  the  fireproofing  must  be 
done  by  another  party,  the  contract  should  be  let  to  some  one  who  is 
familiar  with  that  kind  of  work  and  with  the  material  to  be 
employed. 

Whichever  way  the  contract  is  to  be  let,  however,  it  is  well  for  the 
architect  to  specify  both  the  kind  and  quality  of  the  material  to  be 
employed  and  also  the  way  in  which  the  work  is  to  be  done.  It  is 
also  advisable  and  customary  to  require  that  the  floor  construction 
shall  be  subjected  to  certain  tests  before  it  is  accepted. 


FIREPROOFING.  259 

The  kind  of  material  and  method  of  firepoofing  that  is  to  be 
employed  should  also  be  decided  upon  before  the  framing  plans  are 
made,  as  some  systems  require  different  framing  than  others.  Some 
systems  also  effect  a  sufficient  saving  in  dead  weight  to  enable  lighter 
beams  and  columns  to  be  used  than  are  required  where  heavy  arches 
of  dense  tile  are  used. 

If  competitive  bids  are  desired  to  assist  in  determining  the  kind  of 
fireproofing  to  be  employed,  these  can  usually  be  obtained  before 
the  plans  are  completed,  the  position  of  the  columns  determining  the 
spans  and  width  of  arches. 

If  it  is  decided  to  use  either  porous  or  dense  tile  arches  it  is  not 
absolutely  necessary  to  specify  any  particular  make  of  tile,  but  the 
specifications  may  be  written  so  that  any  tile  may  be  used  which  ful- 
fills the  conditions  therein  contained. 

The  subject  of  fireproof  construction  has  received  a  great  deal  of 
attention  during  the  past  few  years,  and  the  increased  demand  for  a 
safe  and  economical  system  of  fireproofing  has  led  to  the  introduction 
of  many  systems,  nearly  all  of  which,  however,  may  be  said  to  be  still 
in  the  experimental  state.  A  great  many  tests  have  been  made  of 
the  strength  of  fireproof  floors,  but  many  of  these  have  been  con- 
ducted in  such  a  way  as  to  be  of  little  value  in  determining  the  real 
strength  of  the  system.  As  it  is  not  the  purpose  of  this  book  to  enter 
extensively  into  the  subject  of  strength  of  materials,  but  rather  to; 
describe  methods  of  construction,  we  shall  here  undertake  only  to> 
describe  the  methods  of  fireproofing  most  commonly  in  vogue  in  this, 
country,  referring  the  reader  to  the  author's  "  Pocket  Hook,"  and 
•especially  to  a  record  of  tests  on  fireproof  floors  published  in  the 
Brickbuilder  for  1895,  for  more  complete  data  relating  to  their 
strength  and  to  the  designing  of  the  metal  work. 

For  lack  of  space  it  will  also  be  necessary  to  confine  ourself  to  the 
description  of  the  fireproofing  of  buildings  constructed  of  incombus- 
tible materials.  The  fireproofing  of  buildings  constructed  with 
wooden  joist  and  posts  is  now  almost  entirely  confined  to  plastering 
applied  to  some  form  of  metal  lathing,  or  to  plaster  boards  or  blocks. 
These  will  be  described  in  Chapter  XI. 

The  fireproofing  of  non-combustible  buildings  may  be  divided  into 
three  divisions — floor  construction,  partitions  and  the  casings  of 
posts,  girders,  trusses,  etc.  For  convenience  we  will  describe  the  dif- 
ferent methods  under  the  above  headings,  first,  however,  describing 
briefly  the  different  materials  employed  ir  fireproofing. 


26o  BUILDING  CONSTRUCTION. 

FIREPROOFING  MATERIALS. 

289.  Various  materials  have  been  introduced  at  different  times  for 
the  purpose  of  making  buildings  fireproof.     Experience  has  shown, 
however,  that  the  only  practical  method  of  producing  a  really  fire- 
proof building  is  by  using  only  incombustible  materials  for  its  struc- 
tural parts  and  protecting  all  structural  metal  work  with  some  fire, 
water  and  heat-resisting  material.    The  ideal  fireproof  building  would 
undoubtedly  be  one  that  was  constructed  entirely  of  brickwork  and 
terra  cotta,  with  brick,  concrete  or  tile  floors  or  roofs,  built  in  the 
form  of  vaults  sprung  from  brick  piers  and  without  the  employment 
of  structural  metal  work.     Such  a  building,  if  properly  designed  and 
built,  would  withstand  the  combined  action  of  all-  the  elements  for 
centuries.     Modern  commercial  requirements,  however,  demand  that 
the  vertical  supports  shall  be  as  small  and  as  far  apart  as  possible, 
and  that  the  floors  shall  be  thin  and  have  level  ceilings,  and  these 
can  only  be  obtained  by  the  use  of  metal  work. 

The  materials  that  have  been  found  to  successfully  answer  the  pur- 
poses of  modern  fireproofing  are  confined  to  the  products  of  clay, 
some  concretes  and  lime  and  cement  mortars  under  certain  con- 
ditions. 

290.  Cl^y  Products. — Of  all  fire-resisting  materials  burnt  clay 
has  the  most  numerous  applications  in  incombustible  building.     For 
the  construction  of  floors  and  partitions,  and  for  the  casing  of  posts 
and  girders,  the  clay  is  moulded  into  hollow  tiles  or  blocks  of  two 
general  kinds. 

These  are  known  by  several  different  names  :  The  one  by  such  as 
porous  terra  cotta,  terra  cotta  lumber,  cellular  pottery,  porous  tiling, 
soft  tiling,  etc.;  the  other  by  fire  clay  tile,  hollow  pottery,  hard  tile, 
terra  cotta,  dense  tiling,  etc.*  For  convenience  the  first  will  be  here- 
inafter referred  to  as  porous  tiling  and  the  second  as  dense  tiling. 
The  terms  "  hollow  tiling  "  and  "  fireproof  tiling  "  will  be  used  when 
both  are  referred  to  in  a  general  way. 

291.  Porous  tiling  is  formed  by  mixing  sawdust  and  finely  cut 
straw  with  pure  clay  and  submitting  it  to  an  intense  heat,  by  the 
action  of  which  the  sawdust  is  destroyed,  leaving  the  material  light 
and  porous  like  pumice  stone.     When  properly  made  it  will  not  crack 
or  break  from  unequal  heating  or  from  being  suddenly  cooled  by 

•The  Pioneer  Fireproof  Construction  Company  have  also  recently  introduced  a  new  material 
which  they  call  "  semi-porous  hollow  tile."  This  material  is  considerably  lighter  than  the 
dense  tiles  formerly  made  by  them,  and  is  claimed  to  stand  the  fire  and  water  tests  equally  as 
•well  as  porous  tiling. 


FIREPROOFING.  261 

w.ater  when  in  a  heated  condition.  It  can  also  be  cut  with  a  saw  or 
edge  tools,  and  nails  or  screws  may  be  easily  driven  into  it  for  secur- 
ing interior  finish,  slates,  tiles,  etc. 

For  the  successful  resistance  of  heat,  and  as  a  non-conductor,  the 
author  believes  there  is  no  building  material  equal  to  it,  especially 
when  used  in  thin  sections.  To  obtain  the  above  qualities  in  their 
fullest  extent  the  blocks  should  be  manufactured  from  tough  plastic 
clays,  with  which  a  small  percentage  of  fire  clay  should  be  mixed. 

Porous  tiles,  when  properly  made  and  burned,  should  be  compact, 
tough  and  hard,  ringing  when  struck  with  metal.  Poorly  mixed 
pressed  or  burned  tiles,  or  tiles  from  short  or  sandy  clays,  present  a 
ragged,  soft  and  crumbly  appearance,  and  are  not  desirable. 

Porous  tiles  for  floor  construction,  or  wherever  they  may  have  to 
carry  considerable  weight,  should  be  made  with  not  less  than  i-inch 
shells,  and  the  webs  or  partitions  dividing  the  spaces  should  be  from 
£  to  f  inch  thick,  according  to  the  size  of  the  hollows. 

Porous  tiling  possesses  the  advantages  over  hard  tiling  of  being 
light,  tough  and  elastic,  while  dense  tiles  are  hard  and  brittle. 

292.  Dense  tiling  is  made  generally  of  fire  clay,  combined  with  pot- 
ters' clay,  plastic  clays  or  tough  brick  clays,  moulded  by  dies  into  the 
various  hollow  forms  required  for  commercial  use.     The  clay  is  sub- 
jected during  its  manufacture  to  a  high  pressure  while  in  a  moist  or 
damp  state,  which  gives  the  finished  material  great  crushing  strength. 
After  drying  the  tiles  are  burned  like  terra  cotta  in  a  kiln. 

Previous  to  the  year  1890  dense  tiling  was  almost  exclusively  used 
for  the  construction  of  floor  arches,  and  even  at  the  present  day  it 
appears  to  be  more  extensively  used  for  this  purpose  than  the  porous 
tiling,  the  latter  being  confined  principally  to  the  end-method  system 
of  floor  arches. 

Dense  tiling  in  solid  blocks  is  unquestionably  stronger  than  porous 
tiling,  although  more  brittle.  When  made  from  fire  clay  it  is  undoubt- 
edly a  thoroughly  fireproof  and  non-conducting  material,  but  it  will 
not  stand  the  combined  effects  of  fire  and  cold  water  as  well  as  the 
porous  tiling.  In  outer  walls,  exposed  to  the  weather  and  required 
to  be  light,  dense  tiling  is  very  desirable.  Some  manufacturers  fur- 
nish it  with  a  semi  glazed  surface  for  outer  walls  of  buildings.  For 
such  use  it  has  great  durability  and  effectually  stops  moisture. 

In  using  dense  tiling  for  fireproof  filling  care  should  be  taken  that 
the  tiles  are  free  from  cracks  and  sound  and  hard  burnt. 

293.  Concretes. — Concrete  made  of  Portland  cement,  mixed 
with  sand,  crushed  stone,  pieces  of  burnt  fire  clay,  broken  bricks  or 


262  BUILDING  CONSTRUCTION. 

tiles,  has  been  successfully  used  in  Europe  as  a  fireproof  material 
for  many  years,  and  what  few  tests  have  been  made  upon  it  appear 
to  prove  that  it  is  a  highly  fire-resisting  material,  and  it  is  now  so 
considered  by  well-informed  engineers  and  architects. 

Professor  Bauschinger,  of  the  Munich  Technical  School,  tested 
pillars  of  various  materials  by  repeatedly  heating  them  red  hot  and 
then  drenching  them  with  water.  In  his  report  he  says :  "  Of  all 
materials  tested  Portland  cement  concrete  stood  the  best,  and  ordi- 
nary and  clinker  brick  laid  in  Portland  cement  mortar  stood  almost 
equally  as  well." 

Concrete  construction  has  been  largely  used  in  California  for 
many  years  on  account  of  its  fireproof  qualities,  and  it  is  probable 
that  it  will  be  much  more  extensively  used  in  the  future  in  all  por- 
tions of  the  country. 

Plaster  Concretes. — In  Paris  a  composition  of  plaster  of  Paris  and 
broken  brick,  chips,  etc.,  has  been  used  for  generations  for  forming 
ceilings  between  beams,  and  its  durability  is  there  unquestioned.  A 
composition  consisting  of  5  parts  by  weight  of  plaster  of  Paris  and  i 
part  of  wood  shavings,  mixed  with  sufficient  water  to  bring  the  mass 
to  the  consistency  of  a  thin  paste,  has  been  lately  introduced  in  this 
country  in  connection  with  the  Metropolitan  system  of  floor  con- 
struction. It  is  claimed  that  this  material  is  so  remarkable  a  non- 
conductor of  heat  that  a  moderate  thickness  of  it  prevents  the  pass- 
age of  nearly  all  warmth. 

"  In  severe  fire  tests  the  beams  have  remained  cold,  and  con- 
sequently were  unaffected.  When  exposed  to  flame  for  a  long 
time  the  composition  is  attacked  to  a  depth  of  from  ^  to  f  of  an 
inch,  the  remainder  being  unaffected,  and  when  water  is  thrown  upon 
it  the  mass  does  not  fly  or  crack.  When  made  thoroughly  wet  the 
composition  is  not  destroyed." 

This  composition  is  much  lighter  in  weight  than  ordinary  cement 
concrete. 

Lime  mortar,  and  most,  if  not  all,  of  the  hard  mortars  or  patent 
plasters,  when  applied  on  metal  lathing,  will  resist  almost  any  degree 
of  heat,  and  will  withstand  the  action  of  water  for  a  long  time. 

FLOOR  CONSTRUCTIONS. 

294.  The  improvements  in  fireproof  floor  construction  during  the 
past  fifteen  years  have  been  many  and  in  rapid  succession.  Previous 
to  1880  so-called  fireproof  floors  were  constructed  of  brick  arches 
turned  between  the  lower  flanges  of  wrought  iron  I-beams.  These 


FIREPROOFING.  263 

arches,  with  the  concrete  used  for  leveling,  were  very  heavy,  and  as 
the  bottoms  of  the  beams  were  unprotected  and  the  ceiling  formed  by 
the  arches  was  very  undesirable,  brick  arches  soon  gave  place  to 
arches  of  hollow  dense  tile.  The  increased  demand  for  fireproof 
construction,  taken  in  conjunction  with  the  reduction  in  the  prices 
of  steel  and  fireproofing  which  occurred  about  the  year  1889,  led  to 
many  improvements  in  the  designs  for  hollow  tile  floor  arches,  and 
also  to  the  introduction  of  various  systems  of  construction  based 
upon  the  use  of  concrete  and  plaster  compositions,  combined  with 
steel  wires,  bars  and  cables,  used  in  different  shapes  and  in  different 
ways,  the  chief  aim  of  the  inventors  or  designers  being  to  secure  the 
lightest  and  most  economical  floor  consistent  with  ample  strength 
and  thorough  fire  protection. 

In  the  following  pages  the  author  has  endeavored  to  give  an 
impartial  description  of  the  various  systems  at  present  approved  by 
the  leading  architects  and  engineers. 

295.  Hollow    Tile    Floors. — Flat    Construction. — There    are 
three  general  schemes  of  flat  tile  construction  at  present  in  vogue  in 
this  country.     The  first  and  oldest  is  known  as  the  side  method,  in 
which  the  tiles  lie  side  by  side  between  the  beams,  as  shown  in  Figs. 
175,  176  and  177.     In  the  second  scheme,  known  as  the  end  method, 
the  blocks  run  at  right  angles  to  the  beams,  abutting  end  to  end,  as 
shown  in  Figs.  178  and  180.     The  third  method  is  a  cross  between 
the  first  and  second,  the  skewback  (or  abutment)  being  made  as  in 
the  side  construction,  and  the  "interiors"  or  keys  abutting  end  to 
end  between  the  keys,  as  shown  in  Fig.  181.     This  method  is  known 
by  different  names,  such  as  the  "Johnson  Arch,"  "Excelsior  Arch," 
"Combination  Arch,"  etc. 

296.  Side-Method  Arches. — The  hollow  tile  floor  arches  first 
used  in  this  country  were  made  of  dense  tile,  formed  essentially  like 
those  shown  in  Fig.  175,  except  that  no  provision  was  made  for  pro- 
tecting the  bottom  of  the  beams  except  by  the  plaster  on  the  ceiling. 
It  was  soon  found  that  the  bottom  of  the  beams  must  be  more  thor- 
oughly protected  from  heat,  as  when  unprotected  they  warped  and 
twisted  so  badly  during  a  fire  as  to  destroy  the  building.     The  skew- 
backs  were,  therefore,  made  so  as  to  drop  from  |  to  i  inch  below  the 
bottom  of  the  beams,  and  either  to  extend  under  the  beam  or  else  to 
hold  a  thin  tile  dovetailed  between  them,  as  shown  in  the  figure. 
Arches    of    this    type    were    used    for    several  years,   but    it   was 
found  that  they  were   not   strong   enough   to   sustain  severe  loads 


a64  BUILDING  CONSTRUCTION. 

and  the  sudden  strains  caused  by  moving  heavy  safes,  or  to  withstand 
the  rough  treatment  and  heavy  weights  that  floors  are  subjected  to 
while  the  building  is  in  course  of  erection.  The  blocks  were, 
therefore,  strengthened  by  the  introduction  of  horizontal  and  vertical 
webs,  resulting  in  the  shapes  shown  in  Figs.  176  and  177,  which  rep- 
resent the  best  types  of  dense  tile  arches  with  ribs  parallel  to  beams 
made  at  the  present  time. 

Arches  similar  to  these  are  also  made  of  porous  tiling,  but  this 


Fig.  175. 


Fig.  176. 


Fig.  .77. 

material  is  more  generally  used  in  the  end-method  types.  Most  of 
the  side-method  arches  have  beveled  joints,  which  are  parallel  to  the 
sides  of  the  key,  as  shown  in  Fig.  176,  although  arches  are  now  made 
with  radius  joints,  as  shown  in  Fig.  177.  Theoretically  the  latter 
joint  should  make  the  strongest  arch,  but  the  increased  cost  of  mak- 
ing so  many  different  shapes  of  blocks  prevents  it  being  much  used. 
The  blocks  in  the  side-method  arches  break  joint  endways,  so  as 
to  completely  bond  the  arch,  as  shown  in  Fig.  176.  Arches  of  the 
type  shown  in  Figs.  176  and  177  undoubtedly  have  ample  strength 
for  all  ordinary  purposes,  and  the  author  believes  there  is  no  record 


FIREPROOFING. 


265 


of  their  failure  when  in  actual  use  in  buildings.  The  few  compara- 
tive tests  that  have  been  made,  however,  would  appear  to  prove  that 
for  a  given  weight  the  side-method  arch  is  not  as  strong  as  those 
built  on  the  end  method. 

297.  End-Method  Arches.— In  this  method  the  blocks  are 
generally  made  rectangular  in  shape,  with  one  vertical  and  one  hori- 
zontal partition,  and  with  bevel  end  joints.  In  this  system  it  is  not 
the  practice  to  have  the  blocks  in  one  row  break  joint  with  those  in 
another,  as  it  entails  extra  expense  in  setting.  When  this  is  done, 
however,  the  substantialness  of  the  floor  is  increased. 


Fig.  178. 


Fig.  179- 


Fig.  1 80. 

The  most  common  type  of  end-method  arch  is  that  shown  in 
Fig.  178,  which  was  first  brought  into  general  use  by  Mr.  Thomas 
A.  Lee,  and  is  often  designated  as  the  "Lee  End-method  Arch."  It 
has  the  advantage  of  simplicity  and  economy  in  manufacture,  as  all 
the  blocks  for  a  given  depth  of  arch  can  be  made  with  one  die. 
Most,  if  not  all,  manufacturers  making  this  type  of  arch  use  porous 
terra  cotta  in  its  construction.  These  arches  require  verv  heavy 
webs  in  order  to  give  sufficient  bearing  on  the  beams,  which  greatly 
increases  the  weight  of  the  arch.  Fig.  179  shows  an  isometric  view 
of  one  of  the  "  butment  "  pieces  or  hanches. 


266  BUILDING  CONSTRUCTION. 

Some  complaint  has  been  made  by  architects  that  they  find  it  dif- 
ficult to  get  a  strictly  flat  ceiling  with  this  type  of  arch. 

The  open  ends  of  the  hollow  tiles  not  being  well  adapted  to  receive 
mortar  for  the  mortar  joint,  the  mortar  often  squeezes  out,  permitting 
some  of  the  blocks  to  drop  below  the  others. 

As  there  is  no  bond  between  the  rows  of  tiles,  if  a  single  tile  in 
a  row  should  be  broken  or  knocked  out  of  place,  the  entire  row  will 
fall,  and  for  the  same  reason  a  single  tile  cannot  be  omitted  for  mak- 
ing a  temporary  hole,  as  may  be  done  in  side-method  arches. 

Where  the  tile  blocks  abut  endways  they  should  be  cut  to  fit  per- 
fectly between  the  beams,  so  that  the  divisions  will  abut  perfectly 
against  each  other.  Solid  plates  may,  however,  be  placed  between 
the  ends  of  the  tile  blocks  without  injurious  effect,  and,  in  fact,  the 
author  believes  that  such  plates  would  give  a  stronger  joint. 


Fig.  1 80  represents  the  transverse  system  of  floor  arch  construction 
now  made  by  the  Pioneer  Company.  The  interiors  are  of  the  same 
shape  as  those  used  in  their  former  system  (Fig.  181),  sometimes 
called  the  Johnson  Arch,  but  instead  of  using  parallel  abutments  end- 
section  abutments  are  used,  as  shown  in  the  figure.  Whenever  the 
former  system  was  tested  to  destruction  the  abutments  were  almost 
invariably  the  parts  which  failed.  It  was  for  this  reason  that  a  dif- 
ferent style  of  abutment  or  skewback  was  adopted,  and  the  manu- 
facturers claim  that  thev  now  have  the  strongest  and  lightest  flat 
tile  arch  on  the  market.  This  arch  is  made  of  dense  tile,  with  webs 
and  flanges  \  and  £  inches  thick  respectively. 

298.  Combination  of  Side  and  End  Methods.— There  are 
several  styles  of  combination  arches  now  manufactured.  The  object 
in  making  this  shape  of  arch,  is  to  obtain  the  strength  of  the  end- 


FIREPROOFING.  26? 

method  construction  and  at  the  same  time  get  a  flat  bearing  for  the 
skewbacks.  In  order,  however,  to  develop  the  full  strength  of  the 
interior  blocks  the  skewbacks  should  be  made  very  strong  and  with 
several  partitions,  as  they  are  generally  the  weakest  portion  of  the 
arch. 

Fig.  181  illustrates  the  "Excelsior"  dense  tile  arch  made  by 
Henry  Maurer  &  Son.  This  arch  was  patented  by  Mr.  E.  V.  John- 
son, formerly  general  manager  of  the  Pioneer  Company,  and  was  for- 
merly made  also  by  that  company.  The  shape  of  the  interior  blocks 
undoubtedly  gives  great  strength  with  the  minimum  amount  of 
material. 

This  arch  has  been  quite  extensively  used  in  Chicago  and  also  in 
Eastern  cities,  and  apparently  has  given  general  satisfaction. 

An  end-method,  dense  tile  flat  arch,  with  side-method  skewbacks, 
is  also  made  by  the  Empire  Fireproofing  Company.  The  interior 


Fig.  182. 

blocks  have  vertical  and  horizontal  partitions  similar  to  the  Lee  tile, 
but  the  sides  of  the  tile,  instead  of  being  a  true  plane,  have  an  offset 
at  the  middle  of  the  tile,  so  that  one  course  laps  over  the  other, 
thereby  preventing  any  possibility  of  the  tiles  slipping  down,  which 
sometimes  occurs  in  the  ordinary  end-method  arch. 

Fig.  182  shows  a  triple  web  combination  flat  arch  made  by  the 
Hocking  Clay  Manufacturing  Company  and  also  their  patent  flange 
cover  for  beams. 

299.  Depth,  Weight  and  Strength  of  Flat  Tile  Arches.— 
Flat  arches  made  on  the  side-method  principle  may  be  had  in  depths 
from  6  to  12  inches,  and  those  made  on  the  end  method  from  6  to  15 
inches. 

The  depth  of  arch  most  frequently  used  for  office  buildings  and 
retail  stores  is  10  inches,  the  girders  being  spaced  so  as  to  use  lo-inch 
steel  floor  beams  spaced  from  5  to  6  feet  apart.  As  a  rule  the  depth 
of  the  arch  should  be  about  equal  to  the  depth  of  the  beam,  as  it  is 
just  about  as  cheap  and  much  better  construction  to  use  deeper  til- 
ing and  less  concrete  filling. 


268 


BUILDING  CONSTRUCTION. 


The  following  tables  give  the  published  weights  and  safe  span  for 
both  dense  and  porous  tiling  : 

TABLE  X.— WEIGHTS  AND  SPANS  FOR  FLAT  HOLLOW  TILE  ARCHES. 


DENSE   TILE. 


Depth  of  Arch. 

Span  between  Beams. 

Weight  per  sq.  ft. 

6  inches. 
7  inches. 
8  inches. 
9  inches. 
10  inches. 
12  inches. 

3  feet  6  inches  to  4  feet. 
4  feet  to  4  feet  6  inches. 
4  feet  6  inches  to  5  feet  6  inches. 
5  feet  to  5  feet  9  inches. 
5  feet  9  inches  to  6  feet  6  inches. 
6  feet  6  inches  to  7  feet  6  inches. 

22  —  29  pounds. 
27  —  32  pounds. 
30  —  35  pounds. 
32  —  37  pounds. 
34  —  41  pounds. 
37  —  38  pounds. 

POROUS  TILE — END   METHOD. 


6  inches. 

3  feet  to  5  feet. 

21  pounds. 

7  inches. 

3  feet  6  inches  to  5  feet  6  inches. 

24  pounds. 

8  inches. 

4  feet  to  6  feet. 

27  pounds. 

9  inches. 

4  feet  6  inches  to  6  feet  6  inches. 

30  pounds. 

10  inches. 

5  feet  to  7  feet. 

33  pounds. 

12  inches. 

6  feet  to  8  feet. 

37  pounds. 

15  inches. 

7  feet  6  inches  to  10  feet. 

43  pounds. 

The  weight  of  the  Pioneer  Company's  transverse  arches  (Fig.  180), 
as  given  by  the  manufacturers,  is  as  follows : 


DEPTH  OF  ARCH. 

WEIGHT   PER   SQ.  FT. 

DEPTH  OF  ARCH. 

WEIGHT   PER   SQ.  FT. 

8  inches. 
9  inches. 
10  inches. 

22  pounds. 
24  pounds. 
26  pounds. 

12  inches. 
15  inches. 
17  inches. 

30  pounds. 
35  pounds. 
40  pounds.  . 

The  lighter  weights  in  the  third  column  for  dense  arches  are  for 
the  "Excelsior"  arch  ;  the  heavier  weights  are  for  the  arches  shown 
in  Figs.  176  and  177. 

From  a  few  tests  of  the  weight  of  blocks,  as  they  were  being  deliv- 
ered at  the  building,  the  author  is  inclined  to  believe  that  the  actual 
weights  of  both  dense  and  hollow  tile  will  generally  run  at  least  10 
per  cent,  over  those  given  in  manufacturers'  catalogues.  (See  Sec- 
tion 312.) 

The  strength  of  hollow  tile  floors  can  only  be  determined  by  actual 
experiment. 

At  the  tests  made  at  Denver,*  December,  1890,  two  ic-inch  dense 
tile  arches  (s-foot  span),  with  one  horizontal  web  and  built  on  the 
side  method,  failed  under  distributed  loads  of  271  and  428  pounds  per 

•  See  full  account  in  American  Architect  and  Building  News,  March  28,  1891. 


FIREPROOFING.  269 

square  foot,  respectively.  A  porous  tile  end-method  arch,  10  inches 
deep,  with  two  horizontal  webs,  sustained  757  pounds  per  square 
foot  for  two  hours  without  breaking. 

Tests  made  at  Richmond,  Va.,  in  1891  of  6-inch  and  1 2-inch  side- 
method  arches  made  by  the  Empire  Fireproofing  Company,  showed 
a  variation  of  from  288  to  579  pounds  per  square  foot  for  the  6-inch 
arches  and  from  554  to  1,057  pounds  per  square  foot  for  the  1 2-inch 
arches,  the  average  strength  of  the  nine  1 2-inch  arches  being  858 
pounds  per  square  foot. 

The  Pioneer  Company  describe  a  test  of  a  15 -inch  flat  arch  similar 
to  that  shown  in  Fig.  181,  in  which  the  arch  sustained  3,287  pounds 
per  square  foot  (over  an  area  4x4  feet)  before  breaking. 

The  average  breaking  weight  of  five  arches  of  lo-inch  tile,  with 
spans  varying  from  4  feet  1 1  inches  to  5  feet  6  inches,  tested  by  the 
Metropolitan  Company,  was  519  pounds  per  square  foot. 

It  is  generally  considered  by  engineers  that  a  tile  arch  should  not 
fail  under  a  load  less  than  five  times  that  which  it  is  intended  to 
carry.  Arches  of  the  types  shown  in  Figs.  176-182,  inclusive,  if 
properly  set  and  built  of  sound  blocks,  should  be  abundantly  safe  for 
office  floors  and  light  stores  when  proportioned  according  to  the 
table.  The  instances  where  tile  arches  have  failed  when  in  actual 
use  are  very  few  indeed. 

The  cost  of  hollow  tile  arches  of  either  kind,  set  in  place  ready  for 
plastering  in  lots  of  20,000  square  feet,  ranges  from  14  cents  to  25 
cents  per  square  foot,  according  to  size  and  weight  of  the  tile.  In 
Chicago  the  average  price  is  20  cents. 

300.  Manner  of  Setting  Tile  Arches. — Hollow  tile  arches 
of  whatever  type  should  be  set  in  a  good  Rosendale  or  Portland 
cement  mortar  on  plank  centring,  slightly  cambered.  The  best  cen- 
tring for  flat  arches  is  that  in  which  the  planks  run  at  right  angles 
to  the  beams  and  rest  on  2x6  sound  lumber  centre  pieces,  placed  mid- 
way between  the  beams  and  extending  parallel  with  them.  These 
centre  pieces  are  supported  by  T-bolts  from  like  centre  pieces  above, 
crossing  the  beams.  The  planks  on  which  the  tiles  are  laid  should 
b'e  2-inch  plank,  dressed  on  one  side  to  a  uniform  thickness  and  laid 
close  together.  If  the  soffit  tile  is  a  separate  piece  it  should  first  be 
laid  directly  under  the  beam  on  the  planking ;  if  a  projecting  skew- 
back  is  used,  then  the  skewbacks  must  first  be  set,  after  which  the 
centring  is  tightened  by  screwing  down  the  nuts  on  the  T-bolts  until 
the  soffit  tile,  or  skewbacks,  are  hard  against  the  beams  and  the 
planking  has  a  crown  not  exceeding  %  of  an  inch  in  spans  of  6  feet 


2 70  BUILDING  CONSTRUCTION. 

This  system  gives  what  is  very  essential — a  firm  and  steady  centre  on 
which  to  construct  the  flat  tile  work.  The  tiles  should  be  shoved  in 
place  with  close  joints  and  keys  should  fit  close.  The  centres  should 
remain  from  twelve  to  thirty-six  hours,  according  to  condition  of 
weather,  depth  of  tiling  and  mortar  used.  When  centres  are 
"struck"  the  ceiling  should  be  straight,  even,  free  from  open  joints, 
crevices  and  cracks,  ready  to  receive  plastering. 

Wherever  openings  are  required  through  the  floor  they  may  be 
made  by  punching  a  hole  through  the  blocks  ;  or,  if  the  side-method 
arch  is  used,  a  single  block  may  be  omitted.  Small  holes  may  after- 
ward be  plugged  up  with  mortar  and  broken  pieces  of  tile. 

The  variations  in  width  of  spans  between  beams  is  provided  for  by 
supplying  tiles  of  different  sizes,  both  for  interiors  and  keys,  whereby 
a  variety  of  combinations  can  be  secured.  A  great  variety  of  skew- 
backs  are  also  provided  for  fitting  different  sizes  of  beams. 

Tie-Rods. — All  forms  of  flat  or  segmental  tile  arches  require  that 
the  beams  supporting  them  shall  be  bolted  together  with  tie-rods  to 
take  up  the  thrust  of  the  arch.  These  tie-rods  are  usually  f  inch  in 
diameter  and  spaced  from  5  to  7  feet  apart.  They  should  be  secured 
to  the  web  of  the  beam  near  the  bottom  flanges  and  drawn  tightly  in 
place  by  nut  and  thread. 

301.  Protection. — The  laying  of  flat  construction  in  winter 
weather  without  roof  protection  should  not  be  practiced  in  climates 
where  frequent  severe  rain  and  snow  storms  are  followed  by  hard 
freezing  and  thawing,  as  the  mortar  joints  are  liable  to  be  weakened 
or  ruptured,  resulting  in  more  or  less  deflection  of  the  arches.  When 
it  is  intended  to  plaster  on  the  under  side  of  the  arches  the  architect 
should  see  that  the  smoke  and  soot  from  the  boiler  used  for  the  hoist- 
ing plant  are  not  allowed  to  strike  the  arches,  as  neither  can  be 
removed,  and  they  are  sure  to  stain  the  plaster.  For  the  same 
reason  the  architect  should  see  that  only  clean  water  is  used  for  mix- 
ing the  mortar,  and  that  it  is  not  allowed  to  flow  over  the  arches. 

Many  architects  have  had  trouble,  where  flat  tile  arches  have  been 
used,  from  stains  and  excrescence  appearing  on  the  plastered  ceiling 
after  the  latter  had  become  dry.  Such  stains  cannot  always  be  con- 
cealed, even  by  oil  paint,  and  the  only  way  in  which  they  may  be 
avoided  is  by  observing  the  above  precautions  and  not  plastering 
until  the  arches  are  well  dried  out.  A  coating  of  Duresco  applied  to 
the  bottom  of  the  arches  before  plastering  has  been  recommended  as 
a  safe  precaution  against  stains. 


FIREPROOFING.  271 

The  architect  should  also  see  that  the  green  arches  are  not  over- 
loaded with  building  material  by  the  other  contractors. 

302.  Floor  and  Ceiling  Finish.  -The  under  side  of  flat  tile 
arches  is  usually  finished  with  two  coats  of  plaster  applied  directly  to 
the  bottom  of  the  tiles.  If  there  are  inequalities  in  the  surfaces  of 
the  arches  they  should  be  filled  with  natural  cement  and  sand  mor- 
tar before  plastering.  False  plaster  beams  may  either  be  formed  on 
metal  furring,  bolted  to  the  under  side  of  the  arches  and  covered  with 
wire  lathing,  or  the  furring  may  be  of  wood,  as  its  consumption  in 
case  of  fire  would  in  no  way  endanger  the  building.  Metal  furring, 
however,  is  better,  as  it  does  not  shrink. 

Wooden  furring  strips  to  form  nailings  for  wood  mouldings,  etc., 
may  be  secured  to  the  soffits  of  the  arches  by  punching  slot  holes  in 
the  bottom  of  the  blocks  and  inserting  T-headed  bolts. 

The  upper  surface  of  the  arches  is  generally  covered  with  concrete 
of  a  sufficient  depth  to  allow  for  bedding  in  it  the  wooden  strips  to 
which  the  floor  boards  are  nailed. 

The  general  custom  in  regard  to  the  size  of  floor  strips  and  depth 
of  filling  is  to  use  2X4-inch  well-seasoned  wood  strips,  beveled  to  2 
inches  wide  on  top  and  laid  at  right  angles  to  the  beams  and  16 
inches  apart  from  centres.  The  concrete  is  first  leveled  to  the  tops 
of  the  highest  beams  and  the  strips  then  laid  in  place  by  the  carpen- 
ter. The  mason  then  fills  between  the  strips  to  within  \  inch  of 
their  top  with  concrete,  pressed  down  hard  against  the  strips.  A 
single  matched  flooring  is  then  nailed  to  the  wood  strips.  In  New 
York  3X4-inch  strips  are  often  used,  the  strips  being  notched  down 
over  the  beams  i  inch.  The  strips,  also,  do  not  always  run  at  right 
angles  to  the  beams,  although  the  general  opinion  appears  to  be  that 
they  should  do  so  wherever  practicable. 

The  general  custom  amongst  Chicago  architects  is  to  allow  3^ 
inches  from  the  top  of  the  beams  to  the  top  of  the  finished  floor. 
This  gives  a  sufficient  space  between  the  beams  and  flooring  for  run- 
ning gas  pipes  or  water  pipes,  as  shown  in  Fig.  183.  Wherever  build- 
ings are  piped  for  gas,  and  especially  office  buildings,  it  is  absolutely 
necessary  to  leave  sufficient  space  between  the  tops  of  the  steel  beams 
and  the  bottom  of  the  flooring  for  running  branches  to  centre  outlets. 

Wherever  the  nailing  strips  cross  the  floor  beams  or  girders  they 
should  be  fastened  to  them  by  means  of  iron  clamps,  made  so  that 
one  end  can  be  hooked  over  the  flange  of  the  steel  beam  and  the 
other  end  driven  into  the  side  of  the  wood  strip.  When  the  strips 
run  parallel  with  the  beams  it  is  good  practice  to  nail  pieces 


272  BUILDING  CONSTRUCTION. 

of  hoop  iron  across  the  under  side  of  the  strips  about  4  feet  apart, 
to  hold  the  strips  more  firmly  in  place,  as  the  concrete  alone  does 
not  hold  them  with  sufficient  firmness.  The  hoop  iron  strips  should 
be  i£x|  inch  and  10  inches  long,  and  should  be  secured  by  two 
clout  nails. 

The  concrete  used  for  the  filling  on  top  of  the  arches  and  between 
the  nailing  strips  should  be  made  of  screened  boiler  cinders,  mixed 
with  lime  mortar  gauged  with  plaster  of  Paris  or  Portland  cement, 
the  cinders  being  used  on  account  of  their  lightness.  The  concrete 
must  become  thoroughly  dry  before  the  flooring  is  laid.  As  this 
requires  considerable  time,  dry  cinders  without  any  lime  or  cement 
has  been  used  in  a  few  office  buildings  where  it  was  necessary  to  rush 
their  completion.  The  best  architects,  however  do  not  recommend 
the  use  of  dry  cinders  when  it  can  be  avoided. 

Occasionally,  where  the  beams  are  of  unusually  long  span,  a  ic-inch 
or  i2-inch  arch  is  set  between  15  or  20-inch  beams.  In  such  cases 
it  is  better  to  fill  in  on  top  of  the  arches  with  partition  tile  or 
fl-shaped  tile  made  for  the  purpose. 

If  the  floors  are  to  be  tiled  the  concrete  between  the  bottom  of  the 
tiles  and  the  top  of  the  arch  should  be  made  of  Portland  cement, 
sand  and  crushed  stone. 

Wooden  floors  should  be  laid  continuously  over  the  entire  area  to 
be  covered,  without  reference  to  partitions,  where  the  same  are  liable 
to  be  changed  to  suit  tenants.  Permanent  partitions  should  be 
erected  before  the  floors  are  laid. 

Fig.  183  shows  the  floor  construction  used  in  the  "Fair"  Build- 
ing, Chicago,  Jenney  &  Mundie,  architects,  and  also  the  fireproofing 
of  the  columns.  This  cut  is  also  typical  of  many  other  buildings 
recently  erected  in  Chicago. 

303.  Segmental  Tile  Arches. — Where  a  flat  ceiling  is  not 
essential,  and  for  warehouses,  factories,  breweries,  etc.,  the  segmental 
arch  gives  the  strongest,  best  and  cheapest  (considering  the  saving  in 
ironwork)  fireproof  floor  that  can  be  built  of  tile.  Segmental  arches 
can  be  used  for  spans  up  to  20  feet,  thus  dispensing  entirely  with  the 
usual  floor  beams  ;  they  also  effect  a  considerable  saving  in  the  dead 
weight  of  the  floor,  thereby  enabling  the  columns  and  girders  to  be 
made  lighter. 

There  are  at  present  two  distinct  systems  of  segmental  arches  in 
vogue  in  this  country. 

Hollow  Tile  Segmental  Arches. — The  most  common  form  of  seg- 
mental arch  is  that  shown  in  Fig.  184,  which  is  made  of  hollow 


FIREPR  O  OFING. 


273 


blocks,  usually  4,  5,  6  or  8  inches  square  and  12  inches  long,  the  tile 
being  laid  so  as  to  break  joint  longitudinally  of  the  arch.  Nearly  all 
manufacturers  of  hollow  tiling  make  one  or  more  shapes  for  seg- 
mental  arches,  and  also  different  styles  of  skewbacks  to  use  with  them. 
Hollow  tiles  for  segmental  arches  are  also  made  both  of  dense  and 
porous  tiling.  The  latter  is  generally  considered  as  the  best  material 
for  this  purpose.  Segmental  arches  should  have  a  rise  of  not  less 
than  i  inch  per  foot  of  span,  and  \\  inches  wherever  practicable. 


HKEPROOPING 


JSO/AETRIC 


Fig.  183. 


With  this  type  of  arch  it  is  better  to  use  a  very  heavy  or  solid 
skewback  without  the  flange  projection,  as  the  thrust  on  the  skew- 
back  is  very  great  where  the  arch  is  of  wide  span.  The  bottom  flange 
of  the  beam  should  be  covered  with  heavy,  stiffened  wire  lath  before 
the  skewbacks  are  set.  When  plastered  the  ceiling  has  the  appear- 
ance shown  in  Fig.  184. 

If  the  span  of  the  arch  is  not  more  than  8  feet,  hollow  brick,  with 
raised  skewbacks,  may  be  used,  as  shown  in  Fig.  185.  This  makes 
a  very  light  and  strong  floor. 


274 


BUILDING  CONSTRUCTION, 


The  tie-rods  for  segmental  arches  should  be  placed  just  above  the 
bottom  flange  of  the  beam,  as  shown  in  Fig.  184,  and  should  be  pro- 
tected either  by  special  tiling,  made  so  as  to  form  a  paneled  effect  in 
the  ceiling,  or  by  wire  lathing  and  plaster. 


Wire  Lath. 


Fig.  184. 


Weight  and  Strength. — The  following  figures  may  be  taken  as  a  fair 
average  for  the  weight  per  square  foot  of  hollow  brick  or  die  seg- 
mental arches,  exclusive  of  the  concrete  and  plastering  : 

Arches  4  inches  thick,  20  pounds  per  square  foot  ;  safe  span,  8  feet. 
Arches  6  inches  thick,  30  pounds  per  square  foot  ;  safe  span,  16  feet. 
Arches  8  inches  thick,  40  pounds  per  square  foot ;  safe  span,  20  feet. 

The  weight  of  the  concrete  should  be  figured  for  each  special  case, 
allowing  120  pounds  per  cubic  foot  of  concrete.  Plastering  should 
be  taken  at  8  pounds  per  square  foot. 


185. 


The  spans  for  different  thicknesses  should  not  exceed  those  given 
above,  except  that  for  spans  of  20  feet  about  7  feet  of  the  centre  por- 
tion may  be  built  of  6-inch  tile. 

The  segmental  form  of  arch  is  undoubtedly  the  strongest  that  can 
be  built,  whether  of  brick,  hollow  tile  or  concrete. 

In  the  celebrated  Austrian  tests  *  a  common  brick  arch  5^  inches 
thick  and  8  feet  span,  with  a  rise  of  9.85  inches,  carried  an  eccentric 

*  Architecture  and  Building,  January  4,  1896. 


FIREPROOFING.  275 

load  of  885  pounds  per  square  foot  before  failing.  The  failure  was 
then  caused  by  buckling  and  not  by  crushing.  A  porous  tile  arch  of 
15  feet  4  inches  span,  with  a  rise  of  16  inches,  built  with  6-inch  hol- 
low blocks  for  a  distance  of  7  feet  8  inches  across  the  centre  and 
with  8-inch  blocks  for  the  balance,  was  tested  by  loading  one  side 
with  a  pile  of  bricks  measuring  4  feet  6  inches  lengthways  of  the 
arch  and  7  feet  6  inches  widthways.  When  the  weight  reached 
42,000  pounds  (1,235  pounds  per  square  foot)  the  unloaded  side 
commenced  to  buckle,  and  in  30  minutes  collapsed.* 

Segmental  arches,  with  spans  not  exceeding  those  given  above, 
built  with  a  rise  of  i  inch  per  foot  of  span  and  laid  in  good 
cement  mortar,  may  be  safely  relied  upon  to  carry  as  much  as  the 
beams,  when  uniformly  loaded. 

Setting. —  Segmental  arches  are  set  in  the  same  way  as  flat  tile 
arches,  except  that  the  centres  are  arched  to  the  desired  curve  and 
are  suspended  at  the  sides  from  the  beams  or  girders  by  hooks  pass- 
ing over  the  beams.  The  bottoms  of  the  hooks  are  made  round,  and 
have  a  thread  and  wing  nut  for  bringing  the  centre  into  its  proper 
place  and  for  lowering  it  after  the  arch  has  set. 

Holes  are  left  where  the  hooks  pass  through  the  arch,  and  after 
the  centres  are  removed  these  are  substantially  plugged  with  mortar 
and  tile. 

304.  "  Guastavino  "  Arch  (Patented,  and  erected  only  by  R. 
Guastavino). — This  is  the  other  type  of  segmental  tile  arch  referred 
to  in  the  previous  section.  It  is  not  a  true  segmental  arch,  but  is 
constructed  on  the  dome  principle. 

Arch  or  dome  shells  are  built  of  small  rectangular  tiles  of  hard  terra 
cotta  about  6x12  inches  and  i  inch  thick,  cemented  together  in  three 
or  more  thicknesses,  depending  upon  the  size  of  the  vault.  The  tiles 
are  laid  on  arched  centres  one  course  at  a  time,  and  each  course 
breaks  joint  with  that  below.  The  first  layer  is  usually  laid  in  plas- 
ter of  Paris  and  the  others  in  Portland  cement.  The  thickness  of 
the  shell  is  generally  increased  at  the  haunches  or  reinforced  by  a  light 
arch  sprung  against  the  top.  of  the  girder  web.  Each  dome  gener- 
ally covers  the  space  between  four  columns,  girders  being  run  from 
column  to  column  both  ways  of  the  building  and  tied  together  at 
their  ends.  Entire  rooms,  when  surrounded  by  brick  walls  and  not 
more  than  20x40  feet,  may  also  be  covered  by  a  single  vault.  The 

*  Engineering  Record,  April  14,  1894. 


276 


BUILDING  CONSTRUCTION. 


strength  of  these  vaults,  considering  their  thickness,  is  very 
remarkable. 

This  system  does  not  appear  to  be  applicable  to  stores  and  office 
buildings  on  account  of  the  shape  of  the  ceiling,  but  for  public 
buildings  and  buildings  having  solid  masonry  walls  or  piers,  and 
where  a  curved  soffit  is  in  keeping  or  desirable,  it  possesses  great 
advantages.  It  has  been  used  in  a  number  of  buildings  in  New  York 
and  Boston,  and  in  a  few  instances  in  other  cities.  It  was  used 
throughout  the  Boston  Public  Library. 

305.  The  Fawcett  Ventilated  Fireproof  Floor.— This 
floor  is  constructed  of  dense  tile  and  cement  concrete,  and  differs 
entirely  from  those  previously  described. 

The  tiles  are  tubular  in  form,  and,  instead  of  being  made  to  form 
an  arch,  are  used  as  lintels,  as  shown  in  Fig.  186.  They  are  made 


of  fire  or  chimney  pot  clay  in  pieces  about  2  feet  long.  The  floor 
beams  for  this  system  of  construction  are  spaced  2  feet  apart  from 
centres,  and  the  lintels  are  fixed  between  them  with  their  diagonals 
at  right  angles  with  the  beams. 

The  end  of  each  bay  is  squared  by  cutting  (during  manufacture) 
an  ordinary  lintel  parallel  to  the  diagonal  ;  the  piece  cut  off,  when 
reversed,  goes  on  the  other  end.  Thus  the  ends  and  sides  of  all  lin- 
tels are  open  next  the  walls.  These  are  called  "splits." 

The  lintels  being  in  position,  specially  prepared  cement  concrete  is 
filled  in  between  and  over  them,  which  takes  a  direct  bearing  upon 
the  bottom  flange  of  the  beams,  thus  relieving  the  lintels  of  the  floor 
load,  which  is  taken  by  the  iron  and  concrete,  the  lintels  forming  a 
permanent  fireproof  centring,  reducing  the  dead  weight  of  the  floor 
about  25  per  cent,  and  saving  about  half  the  concrete. 

The  lintels  bear  on  the  beams  in  such  a  way  as  to  entirely  encase 


FIREPROOFING. 


277 


the  bottom  flange  without  being  in  contact  with  it,  a  clear  |-inch 
space  being  left  for  the  passage  of  air. 

The  peculiar  feature  of  this  system  is  the  circulation  of  air  pro- 
vided through  the  tubular  lintels  and  under  the  flanges  of  the  beams. 
Cold  air  is  admitted  (through  air  bricks  in  the  external  walls)  into  a 
portion  of  the  open  ends  or  sides  of  the  lintels,  and  passes  through 
them  from  bay  to  bay  under  the  beams,  both  transversely  and  longi- 
tudinally of  the  floor,  as  shown  in  Fig.  187. 

It  is  claimed  that  the  chief  fire-resisting  agent  in  this  floor  is  not 
so  much  the  terra  cotta  or  the  concrete  as  the  cold  air,  and  that  the 
circulation  of  air  through  the  floor  and  around  the  beams  will 
actually  prevent  the  iron  from  ever  getting  hot. 

The  Fawcett  Company  claim  that  their  floors  have  never  been 
injured  by  fire  and  water  beyond  what  could  be  repaired  by  replas- 
tering  the  ceiling  and  redecorating  the  walls. 


Fig.  187. 

The  steel  floor  beams,  being  spaced  so  near  together,  can  be  made 
very  light  (5 -inch  beams  being  generally  used  for  office  floors, 
schools,  etc.,  up  to  16  feet  span),  and  as  the  total  thickness  of  the 
floor  from  under  side  of  plaster  to  top  of  flooring  is  but  5  inches 
greater  than  the  depth  of  the  beams,  the  floors  are  consequently  much 
thinner  than  in  almost  all  other  systems. 

The  floor  is  finished  on  top  by  bedding  2X3-inch  nailing  strips  in 
the  concrete  above  the  steel  joist,  as  shown  in  Fig.  187,  and  nailing 
the  flooring  to  these  strips  in  the  usual  way. 

Repeated  tests  have  proven  that  the  strength  of  the  tile  and  con- 
crete filling  is  fully  equal  to  that  of  the  beams,  so  that  the  carrying 
capacity  of  the  floor  is  only  limited  by  that  of  the  beams.  For  beam 
spans  not  exeeding  18  feet,  the  cost  of  the  structural  steel  work  in 
place  does  not  exceed  that  of  the  structural  work  for  the  flat  arches 
previously  described. 

The  advantages  claimed  for  this  system,  aside  from  its  fireproof 


278  BUILDING  CONSTRUCTION. 

qualities,  are  :  Saving  in  height  of  story  from  6  to  8  inches  ;  saving 
in  freight,  hauling  and  hoisting,  of  about  50  per  cent. 

No  tie-rods  are  required,  and  a  more  even  distribution  of  the  floor 
weight  on  the  walls  is  secured.  No  centres  are  required  for  setting, 
and  ordinary  unskilled  labor  can  be  employed  for  all  portions  of  the 
work. 

The  weight  of  the  floor  is  much  lighter  than  that  of  any  other  sys- 
tem using  tile  rilling  between  the  beams,  with  the  possible  exception 
of  the  Guastavino  floor. 

This  floor  has  been  placed  in  a  great  many  fine  buildings  in  Eng- 
land, and  lately  in  many  buildings  in  Philadelphia  and  other  Eastern 
cities.  It  certainly  has  many  good  points  and  deserves  investigation, 

306.  Concrete  and  Metal  Floors. — Within  a  few  years  sev- 
eral styles  of  fireproof  floor  construction,  based  upon  the  use  of  con- 
crete in  combination  with  iron  or  steel  in  various  shapes,  have  been 
introduced  in  this  country,  and  a  few  of  them  have  proved  strong 
competitors  of  the  hollow  tile  floor.  The  chief  aim  in  the  introduc- 
tion of  these  systems  has  been  to  obtain  a  floor  that  shall  have  the 
strength  and  fireproof  qualities  of  the  tile  floor,  and  at  the  same  time 
be  lighter  and  less  expensive. 

There  are  two  general  classes  of  concrete  floor  construction.  The 
first  class  consists  of  tension  member  floors,  which  in  themselves  fur- 
nish the  necessary  strength  for  sustaining  the  floor  from  wall  to  wall, 
or  wall  to  girder,  without  the  use  of  floor  beams  ;  and  the  other  class 
consists  of  I-beams  5  or  6  feet  apart  for  sustaining  the  floor,  with 
rods  or  bars  suspended  or  resting  upon  the  beams,  supporting  wire 
cloth,  netting  or  expanded  metal,  which  carries  the  concrete  or  plas- 
ter filling.  Prominent  among  the  first  devices  mentioned  are  the 
Hyatt  ribbed  metal  ties  and  Portland  cement  concrete  floors  built  by 
P.  H.  Jackson,  San  Francisco  ;  the  concrete  and  twisted  bar  floors 
built  by  the  Ransome  &  Smith  Company,  of  Chicago  ;  and  the  Lee 
hollow  tile  and  cable  rod  floors  built  by  the  Lee  Fireproof  Construc- 
tion Company,  of  New  York. 

Prominent  among  the  I-beam  and  concrete  filling  devices  are  the 
systems  of  the  Metropolitan  Freproofing  Company,  of  Trenton,  N.  J.; 
the  expanded  metal  construction  companies  of  St.  Louis  and  New 
Yorkfthe  arch  construction  of  the  Roebling  system  and  the  flat  beam 
construction  of  the  Columbian  Fireproofing  Company. 

While  concrete  has  been  used  in  construction  to  resist  compressive 
stress  for  many  centuries,  it  was  not  until  1876  that  an  attempt  was 
made  to  form  concrete  beams  by  imbedding  iron  in  the  bottom  to 

*  For  description  see  page  406. 
A 


FIR  EPR  O  OFING.  2  7  9 

afford  the  necessary  tensile  strength  which  the  concrete  lacked.  The 
idea  was  conceived  by  Mr.  Thaddeus  Hyatt,  an  inventor,  who  made 
many  experimental  beams,  with  the  iron  introduced  in  a  great 
variety  of  ways,  as  straight  ties,  with  and  without  anchors  and  wash- 
ers ;  truss  rods  in  various  forms,  and  flat  pieces  of  iron  set  vertically 
and  laid  flat  and  anchored  at  intervals  along  the  entire  length.  These 
experimental  beams  were  tested  and  broken  by  Mr.  David  Kirkaldy, 
of  London,  and  the  results  proved  that  the  iron  could  be  perfectly 
united  with  the  concrete  and  that  it  could  be  depended  upon  for  its 
full  tensile  strength. 

The  method  Mr.  Hyatt  finally  adopted  as  the  best  for  securing  per- 
fect unison  of  the  iron  and  concrete  was  to  use  the  iron  as  thin  vertical 
blades  placed  near  the  bottom  of  the  concrete  beam  or  slab,  and  ex- 
tending its  entire  length  and  bearing  on  the  supports  at  both  ends  ; 
these  vertical  blades  to  be  anchored  at  intervals  of  a  few  inches  by 
round  iron  wires  threaded  through  holes  punched  opposite  each  other 
in  the  blades,  thus  forming  a  gridiron,  which  was  completely  imbed- 
ded in  the  concrete. 

The  first  person  in  this  country  to  make  a  practical  application  of 
Mr.  Hyatt's  discovery  was  Mr.  P.  H.  Jackson,  of  San  Francisco, 
Cal.,  who  has  used  a  combination  of  concrete  and  Hyatt's  ties  quite 
extensively  in  that  city  for  covering  sidewalk  vaults  and  for  the  sup- 
port of  store  lintels  ;  also  for  self-supporting  floors. 

Tests  of  concrete  beams  made  by  Mr.  Jackson  are  described  in  the 
Architects'  and  Builders'  Pocket  Book. 

307.  The  Ransome  &  Smith  Floor.— While  Mr.  Jackson 
was  experimenting  with  the  Hyatt  ties,  Mr.  E.  L.  Ransome,  a  very 
successful  worker  of  concrete  in  San  Francisco,  conceived  the  idea 
of  using  square  bars  of  iron  and  steel,  twisted  their  entire  length,  in 
place  of  the  flat  bars  and  wires  used  by  Mr.  Jackson,  as  shown  in 
Fig.  1 88.  It  was  found  that  these  bars  were  held  in  the  concrete 
equally  as  well,  if  not  better,  than  the  other,  and  that  they  were  much 
less  expensive.  None  of  the  iron  in  the  ties  is  wasted,  and  it  has 
been  demonstrated  by  careful  experiments  that  the  process  of  twist- 
ing the  bars  to  the  extent  desired  strengthens  the  rods  instead  of 
weakening  them. 

Mr.  Ransome  patented  his  improvement  in  1884,  and  since  that 
time  it  has  been  extensively  used  in  San  Francisco. 

The  Ransome  concrete  floors  are  made  in  two  forms — flat  (Fig.  188) 
and  recessed,  or  paneled  (Fig.  188  A).  These  floors  have  been  used 
for  spans  up  to  34  feet.  No  floor  beams  are  required,  the  floor  being 


z8o 


B  UILDING  CONS  TR  UCTION. 


self-supporting  from  wall  to  wall  (when  the  building  is  not  more  than 
30  feet  wide),  or  from  wall  to  girder.  The  great  strength  of  these 
floors  has  been  fully  demonstrated  by  actual  use  in  many  heavy  ware- 


Tension 


AuxiUaru  Bar— ^ 


houses  in  various  portions  of  California,  as  well  as  in  many  other 
buildings. 

A  section  of  a  flat  floor  in  the  California  Academy  of  Science, 
15x22  feet,  was  tested  in  1890  with  a  uniform  load  of  415  pounds  per 
square  foot,  and  the  load  left  in  place  for  one  month.  The  deflection 


Fig.  1 88  A. 


at  the  centre  of  the  2  2 -foot  span  was  only  |  inch.  It  was  estimated 
by  the  architects  that  the  saving  by  using  this  construction  throughout 
the  building,  over  the  ordinary  use  of  steel  beams  and  hollow  tile 
arches  of  the  same  strength,  and  with  similar  cement-finished  floors 
on  top,  amounted  to  fifty  cents  per  square  foot  of  floor. 


FIREPROOFING.  281 

The  flat  construction  shown  in  Fig.  188  is  the  best  adapted,  of  the 
two,  for  office  buildings,  hotels,  etc.,  although  the  paneled  floor, 
shown  in  Fig.  i88A,  has  much  the  greater  strength  for  the  same 
amount  of  material.  The  latter  construction  has  been  used  in  sev- 
eral warehouses  in  California  without  the  use  of  any  steel  or  iron 
beams  or  girders,  and  has  supported  very  heavy  loads  for  several 
years. 

As  a  fireproof  construction  this  system  is  undoubtedly  equal  to  any 
other  construction  in  use.  The  patents  controlling  the  use  of  twisted 
bars  in  combination  with  concrete  are  now  owned  by  the  Ransome 
&  Smith  Co.,  of  Chicago,  from  whom  more  complete  information 
of  their  system  of  flooring  may  be  obtained. 

308.  The  Lee  Hollow  Tile  and  Cable  Rod  Floor.— 
Mr.  Thomas  A.  Lee,  the  originator  of  the  end  system  of  hollow  tile 
arches,  about  the  year  1890  patented  a  system  of  floor  construction 
which  is  the  same  in  principle  as  the  Ransome  floor.  Instead  of 


Fig.  i89.-Lee   Floor. 

using  concrete  to  resist  the  compressive  stress,  hollow  porous  tile 
blocks  with  square  ends  and  a  rod  groove  along  one  side  near  the 
base  are  used,  as  shown  in  Fig.  189.  The  tension  member  con- 
sists of  cables  made  of  round,  drawn  steel  rods  of  about  T3g-  of  an 
inch  in  diameter  laid  spirally  together,  usually  in  two  strands.  The 
rods  are  spaced  8,  10  or  12  inches  apart,  according  to  the  span  and 
width  of  tile,  and  are  buried  in  soft  Portland  cement  placed  in  the 
grooves  near  the  bottom  of  the  tile.  The  cement  unites  the  tiles  and 
cables  so  as  to  form  a  composite  beam.  The  floors  extend  like  a 
flat  plate  from  wall  to  wall,  or  from  girder  to  girder,  their  thickness 
being  about  f  inch  for  each  foot  of  span. 

Floors  and  roofs  similar  to  the  above  have  been  built  in  various 
costly  buildings  in  different  portions  of  this  country  and  in  Canada, 
the  spans  varying  from  10  to  28  feet. 

In  buildings  having  solid  brick  or  concrete  walls  and  partitions, 
these  tension  member  floors  may  be  used  to  good  advantage,  but  it  is 
doubtful  if  they  ever  come  into  general  use  in  buildings  built  on  the 
skeleton  principle.  They  require  very  careful  and  faithful  workman- 
ship and  the  very  best  quality  of  cement  to  make  them  safe. 


282 


BUILDING  CONSTRUCTION. 


309.  The  Metropolitan  Floor. — This  floor,  which  was  for  a 
time  known  as  the  "  Manhattan  "  system,  and  is  protected  by  letters 
patent,  is  constructed  as  follows  :  Cables,  each  composed  of  two  gal- 
vanized wires  (usually  of  No.  12  gauge)  twisted  together,  are  sus- 
pended between  the  top  of  I-beams,  as  shown  in  Fig.  190,  and  spaced 
from  i  inch  to  \\  inches  apart,  according  to  the  load  which  is 
to  be  carried.  The  ends  of  the  cables  are  secured  to  the  beams  by 
means  of  hooks  3  inches  long  made  of  J-inch  square  iron,  which 
grasp  the  upper  flange.  A  length  of  gas  pipe  is  laid  over  the  cable 
midway  between  the  beams  to  give  them  a  uniform  sag.  Forms  or 
centres  are  then  placed  under  the  cables,  and  a  composition  consist- 
ing of  5  parts,  by  weight,  of  plaster  of  Paris- and  i  part  of  wood  shav- 
ings, mixed  with  sufficient  water  to  make  a  thin  paste,  is  poured  on. 


Hook 


Fig.  190. 


As  plaster  of  Paris  sets  very  quickly  the  resulting  floor  is  sufficiently 
strong  to  be  used  at  once  under  loads,  with  a  surface  uniform  and 
level  above  the  top  of  the  bearrvs. 

Where  a  paneled  ceiling  can  be  used  wire  netting  is  stretched  over 
the  beams  and  the  same  composition  poured  around  them,  fireproof- 
ing  the  beam,  as  shown  at  £,  Fig.  191.  Where  a  flush  ceiling  is 
required  flat  bars  are  placed  on  the  bottom  flanges  of  the  beams  and 
wire  netting  stretched  over  them.  Forms  are  then  placed  under- 
neath and  the  same  composition  as  in  the  floor  plate  poured  on,  form- 
ing a  plate  about  i£  inches  thick  and  extending  i  inch  below  the  bot- 
tom of  the  beams,  as  shown  at  A,  Fig.  191. 

The  usual  thickness  of  the  floor  plate  is  4  inches,  with  beam  spac- 
ings  of  from  4  to  6  feet.  It  will  be  seen  that  in  principle  this  floor 
closely  resembles  the  Ransome  tension  bar  system,  as  the  cables  take 
up  the  tension  and  the  concrete  resists  the  compressive  stress.  This 
combination  of  steel  (in  its  strongest  shape)  with  concrete  is  theoret- 


FIR  EPROOFING. 


283 


ically  one  of  the  most  perfect  forms  of  fireproof  construction,  and 
although  defects  may  be  discovered  in  the  details  of  construction, 
the  system  itself  seems  destined  to  become  of  wide  application. 

No  tie-rods  between  the  beams  are  required  in  this  system,  as  the 
floor  plate  is  practically  a  beam,  and  transmits  only  a  vertical  pres- 
sure to  the  I-beams. 

The  tests  that  have  been  made  of  this  floor  construction  seem  to 
prove  that  it  is  thoroughly  fireproof  and  heat-resisting,  and  that  its 
ultimate  strength  for  floor  plates  4  inches  thick  and  6  feet  span  is 
about  1,500  pounds  per  square  foot,  while  loads  as  high  as  2,000 
pounds  have  been  supported  by  it. 

The  remarkably  light  weight  of  this  floor  is  one  of  its  chief  advan- 
tages, the  average  weight  of  the  floor  plate  being  about  18  pounds 
per  square  foot,  and  the  weight  of  the  ceiling  plate,  without  the  plas- 
tering, 6  pounds.  A  floor  constructed  by  this  method  with  I-beams 


Fig.  191. 

-6  feet  apart  would  therefore  weigh,  when  all  complete  and  ceiling 
plastered,  less  .than  half  as  much  as  the  old  style  dense  tile  systems. 

The  greatest  objection  thus  far  brought  against  this  floor  is  the 
great  amount  of  water  used  in  its  construction  and  the  time  required 
for  the  wood  shavings  to  dry  out. 

310.  Mr.  J.  Hollis  Wells,  C.  E.,  in  reviewing  some  tests  of  fire- 
proof floors  made  at  Trenton,  N.  J.,  in  1894,  makes  the  following 
comparison  between  the  concrete  and  wire  and  hollow  tile  floors: 
"  The  method  of  suspending  a  fireproof  material  on  wires  of  proper 
strength  from  beam  to  beam  makes  a  strong  homogeneous  floor, 
absolutely  fireproof,  and  each  bay  or  section  independent  of  those 
adjoining.  The  hollow  tile  arch,  creating  a  thrust  on  the  floor  beams, 
depends  on  tie-rods  to  counteract  it.  Tie-rods  seldom  set  in  proper 
place,  oftentimes  are  not  screwed  up  tight,  and  the  construction  is 
weakened.  In  the  suspended  floor  tie-rods  are  not  used  at  all ;  beam 
is  tied  to  beam  from  upper  flange  to  upper  flange,  and  a  rigid  base 
extends  clear  across  the  floor  from  wall  to  wall."  * 


f  Engineering  Record,  December  22,  1895. 


284  BUILDING  CONSTRUCTION. 

Various  styles  of  floors  have  been  constructed  on  the  principle  of 
the  Metropolitan  floor,  although  nearly  all  use  Portland  cement  con- 
crete instead  of  the  plaster  composition.  Wire  lathing,  expanded 
metal,  and  various  shaped  bars  are  used  for  the  tension  members. 

The  principal  advantage  sought  in  these  floors  over  the  terra  cotta 
tile  arches  is  a  reduction  in  the  weight  of  the  floor,  thereby  causing  a 
saving  in  the  steel  construction.  The  floors  themselves  are  also,  as  a 
rule,  a  little  cheaper  than  the  tile  floors. 

The  strains  in  floors  of  this  kind  are  the  same  as  in  those  of  a  beam, 
the  effect  of  the  load  being  to  pull  the  tension  members  apart  at  the 
bottom  and  to  crush  the  concrete  on  top.  When  the  concrete  is  of 
the  proper  thickness,  and  of  good  quality,  the  strength  of  the  floor 
will  be  determined  by  the  strength  of  the  tension  members. 

Several  tests  of  beams  made  of  Portland  cement,  concrete  and  wire 
netting  made  by  the  New  Jersey  Wire  Cloth  Company,  appear  to 
show  that  only  about  one-half  the  strength  of  the  tension  members 
(when  of  wire  cloth)  can  be  developed.  In  all  floors  constructed  of 
concrete,  plaster  or  tile,  with  steel  tension  members,  it  is  of  the  first 
importance  that  the  two  materials  shall  be  so  closely  united  that  the 
tension  members  will  not  be  drawn  through,  or  slip  in  the  concrete, 
for  the  minute  this  occurs  the  strength  of  the  floor,  as  a  beam,  is 
destroyed.  To  secure  this  perfect  adhesion,  it  is  necessary  that  the 
materials  and  work  shall  be  of  the  best  quality  and  not  slighted  in 
any  way. 

311.  The  Roebling  Patent  Fireproof  Floor.  *— This  also 
is  a  concrete  construction,  but  the  concrete,  instead  of  being  used  as 
a  beam,  is  entirely  in  compression,  the  strength  of  the  floor  being  due 
to  the  resistance  of  the  concrete  acting  as  an  arch. 

The  method  of  forming  the  floor  and  ceiling  is  well  illustrated  by 
Fig.  192.  The  floor  construction  consists  of  a  wire  cloth  arch,  stiff- 
ened by  steel  rods,  which  is  sprung  between  the  floor  beams  and 
abuts  into  the  seat  formed  by  the  web  and  lower  flange  of  the  I-beams. 
On  this  wire  arch  Portland  cement  concrete  is  deposited  and  allowed 
to  harden,  making  a  strong  monolithic  arched  slab  between  the 
beams.  The  ceiling  construction  consists  of  supporting  rods  attached 
to  the  lower  flanges  of  the  floor  beams  by  a  patent  clamp,  which  off- 
sets the  rods  below  the  I-beams.  Under  these  rods,  and  securely 
laced  to  them,  is  placed  the  Roebling  standard  lathing,  with  the 
stiffening  rods  crossing  the  supporting  rods  at  right  angles.  This 

*  Controlled  by  the  John  A.  Roebling's  Sons  Co. 


FIREPROOFING. 


285 


construction  produces  a  ceiling  that  is  uniformly  level  over  its  entire 
surface,  requiring  the  same  amount  of  plaster  over  all  portions.  The 
ceiling  being  separate  from  the  floor  is  not  liable  to  stains,  as  is  fre- 
quently the  case  with  tile  construction. 

The  weight  of  finished  floor  and  ceiling,  including  the  plastering 
underneath  and  two  thicknesses  of  wood  flooring,  as  given  by  the 
Roebling  Co.,  varies  from  28  to  53  pounds  per  square  foot,  according 
to  the  span  and  depth  of  beams  or  girders.  This  is  exclusive  of  the 
steel  beams.  [See  also  page  405.] 

The  strength  of  this  floor  depends,  of  course,  almost  entirely  upon 
the  concrete — the  quality  and  proportion  of  the  ingredients  and  the 
mixing. 


Fig.  192. 

Thus  far,  where  the  system  has  been  used,  only  the  best  grades  of 
imported  Portland  cement  and  the  best  sharp  sand  have  been  used. 
For  dwellings  and  buildings  in  which  the  live  load  never  exceeds  100 
pounds  per  square  foot,  a  concrete  made  of  cement,  sand  and  first- 
class  cinder  may  be  employed,  with  a  saving  in  weight  and  cost,  and 
at  the  same  time  with  ample  strength. 

Various  tests  of  these  floors  built  by  the  Roebling  Sons'  Co.,  with 
spans  varying  from  4^  to  5  feet,  have  shown  a  carrying  capacity,  with 
no  signs  of  failure,  of  from  1,000  to  2,400  pounds  per  square  foot.f 
Further  evidence  of  the  strength  of  such  floors  is  also  furnished  by 
the  celebrated  "  Austrian  "  tests  on  concrete  arches.*  In  these  tests 
a  concrete  arch  only  3  inches  thick  and  span  of  4^  feet,  without 

*  See  Architecture  and  Building  January  4,  1895.  +  See  also  page  405. 


286  BUILDING  CONSTRUCTION. 

filling  above  the  haunches,  sustained  1,638  pounds  per  square  foot 
over  the  entire  area  without  failure  or  cracking,  while  a  similar  arch, 
3^  inches  thick,  with  span  of  8  feet  10  inches  and  rise  of  io£  inches, 
sustained  an  eccentric  load  over  one-half  of  the  arch  of  1,130  pounds 
per  square  foot.  The  arch  then  failed  by  buckling,  and  not  by  com- 
pression. 

The  strength  of  the  Roebling  floor,  therefore,  may  be  considered 
ample  for  any  load  that  may  be  applied,  provided  the  concrete  is  of 
sufficient  thickness  at  the  crown  and  of  good  quality. 

The  most  economical  proportions  for  this  floor,  considering  also 
the  cost  of  the  steel  beams,  will  generally  be  obtained  by  using 
lo-inch  I-beams,  spaced  as  far  apart  as  the  loads  will  permit. 

Aside  from  its  strength  and  fireproof  qualities,  this  construction 
possesses  many  practical  advantages,  a  few  of  which  may  be  briefly 
mentioned  :  A  perfectly  flat  ceiling,  which  may  be  placed  any  dis- 
tance below  the  beams  and  which  is  not  liable  to  discoloration  ;  a 
continuous  air  space  between  floor  and  ceiling ;  it  is  much  lighter 
than  many  of  the  tile  floors,  and  can  be  adapted  to  any  building  or 
to  any  load.  The  ceilings  may  be  either  flat,  paneled  or  arched. 

No  special  arrangement  of  floor  beams  is  required,  and  the  spac- 
ings  need  not  be  uniform. 

The  floor  is  not  easily  damaged  j  openings  of  any  size  may  be  cut 
through  the  concrete  to  neat  dimensions,  the  wire  cloth  preventing 
the  concrete  from  flaking  away  on  the  under  side. 

Where  buildings  must  be  erected  with  great  rapidity,  or  in  winter 
weather,  this  system  is  especially  desirable.  No  wood  centring  is 
required,  and  as  the  arch  wire  is  made  to  dimensions  and  bent  to  the 
correct  curve  at  the  mill,  the  wire  arches  can  be  put  in  place  very 
quickly  and  in  tmy  kind  of  weather.  Once  in  place  they  afford  a 
protection  to  workmen,  as  they  possess  sufficient  strength  in  them- 
selves to  sustain  a  considerable  load,  or  to  intercept  a  person  falling 
from  the  beams  above.  The  wire  arches  are  generally  set  so  as  to 
keep  within  two  stories  of  the  masons.  As  Portland  cement  is  used 
for  the  concrete,  the  latter  can  also  be  safely  mixed  in  quite  cold 
weather.  The  floors  are  safe  and  available  for  use  two  days  after  the 
concrete  has  been  applied. 

The  cost  of  this  system  should  not  exceed  that  of  other  systems 
using  Portland  cement  or  tile,  and  in  many  instances  would  probably 
be  less. 


FIR&PR  O  OFING.  2  8  7 

312.  The  "  Columbian  "  System  of  Fireproof  Floors.*— 

This  system  is  also  one  of  concrete  construction,  the  shape  of  the  con- 
crete being  very  much  the  same  as  in  the  Metropolitan  floor.  In  this 
floor,  however,  the  concrete,  instead  of  being  supported  by  wires  or 
netting,  is  supported  by  ribbed  steel  bars  of  a  special  shape,  suspended 
from  the  steel  I-beams  and  supported  on  edge  by  means  of  steel  stir- 
rups, which  have  the  profile  of  the  bar  cut  in  them,  as  shown  in 
Fig.  193.  After  the  bars  are  set  in  place  a  wooden  form  is  suspended 
beneath  them  and  a  layer  of  Portland  cement  concrete  is  laid  on  top, 
flush  with  the  top  of  the  beams  and  completely  surrounding  the 
ribbed  steel  bars. 

If  a  level  ceiling  beneath  the  beams  is  desired  it  is  constructed 
independently  of  the  floor  by  using  i-inch  section  ribbed  bars,  resting 

on  the  bottom  flanges  of  the 

^W  I-beams,  and  filling  between 
and  around  them  with  con- 
crete, in  the  same  way  as  is 
done  for  the  floors. 

The  system  of  floor  and 
ceiling  construction  is  plainly 
shown  by  the  section  drawing, 
Fig.  194. 

Three  sizes  of  bars  are  used 
for  the  floor  construction — 
2^-inch,  2-inch  and  i|-inchr 

and  these  are  spaced  at  different  distances  apart,  according  to  the 
span  and  the  weight  to  be  supported.  The  2^-inch  bars  are  used  only 
in  warehouses,  heavy  storage  buildings,  etc.;  the  2 -inch  bar  for  floors 
in  office  buildings  and  where  the  loads  do  not  exceed  200  pounds  per 
square  foot.  The  i^-inch  bar  gives  sufficient  strength  for  floors  in 
residences,  apartment  houses,  etc.  The  shape  of  the  2-inch  and 
2^-inch  bars  is  shown  by  the  hole  in  the  stirrup,  Fig.  193.  The 
i  ^-inch  bar  has  only  one  rib.  The  stirrups  are  made  of  2x^-inch 
steel.  The  usual  spacing  of  the  bars  is  about  20  inches. 

The  concrete  recommended  by  the  Columbian  Co.,  and  generally- 
used,  is  composed  of  i  part  Portland  cement,  2  of  sand  and  5  of 
crushed  furnace  slag,  although  broken  brick  and  certain  kinds  of  rock 
are  also  sometimes  used. 

The  most  economical  spacing  of  the  floor  beams  for  this  construction 


:  Patents  controlled  by  the  Columbian  Fireproofing  Co. 


288 


BUILDING  CONSTRUCTION. 


is  6  feet  from  centre  to  centre  of  beams  for  the  double  construction 
shown  in  Fig.  194  and  7  feet  for  paneled  construction,  although  either 
construction  can  be  adapted  to  spans  up  to  8  feet.  It  is  also  not 
necessary  that  the  spacing  of  the  beams  be  uniform,  and  no  special 
framing  is  required  for  this  system,  as  it  pan  be  readily  adapted  to 
any  plan  suitable  for  any  of  the  flat  floor  constructions  described, 
although  with  this  system  the  beams  can  often  be  made  lighter  or 
spaced  farther  apart,  owing  to  the  decreased  dead  weight  of  the  floor. 
In  most  classes  of  buildings  other  than  offices  and  dwellings  the 
double  construction  is  not  necessary,  as  the  bottom  of  the  floor 
construction  answers  for  the  ceiling,  and  by  enclosing  the  beams  and 
girders  with  concrete  or  tile,  a  neat  paneled  effect  is  produced,  and 


Fig    194. 

the  height  of  the  story  increased  or  the  total  height  of  the  building 
decreased,  as  preferred. 

Fig.  195  shows  two  styles  of  girder  casings  used  in  connection 
with  this  system,  both  providing  for  an  air  space  completely  around 
the  steel.  The  casing  shown  at  A  is  made  of  concrete  slabs,  sup- 
ported by  iron  clamps  or  ties,  which  are  completely  imbedded  in  and 
insulated  by  the  bottom  slab— a  very  important  provision.  The  cas- 
ing shown  at  B  is  made  of  hollow  tile,  thus  providing  two  air  spaces 
on  each  side  of  the  beam  and  one  underneath.  Concealed  anchors 
are  also  used  for  this  casing. 

This  floor  may  be  finished  on  top  in  the  usual  way  by  imbedding 
nailing  strips  in  cinder  filling,  or  2^xi|-inch  strips  (not  beveled)  may 
be  nailed  directly  to  the  concrete  floor  and  the  filling  omitted.  Nail- 
ing strips  have  been  applied  in  this  manner  in  several  large  build- 
ings, and,  it  is  claimed,  with  the  best  results. 


FIREPROOFING. 


289 


The  weight  of  this  system  of  floor  construction,  exclusive  of  the 
I-beams,  plastering,  nailing  strips  and  flooring,  is  as  follows  : 

For  2i-inch  bars,  4  inches  of  concrete,  40  pounds  per  square  foot. 
For  2-inch  bars,  3  inches  of  concrete,  30  pounds  per  square  foot. 
For  i^-inch  bars,  2\  inches  of  concrete,  24  pounds  per  square  foot. 

The  level  ceiling  shown  in  Fig.  194  (2  inches  thick)  weighs  20 
pounds  per  square  foot. 

Strength. — The  Columbian  Co.  guarantee  that  their  3-inch  floor,  6 
feet  span,  will  support  200  pounds  per  square  foot ;  the  4-inch  floor, 
6  feet  span,  600  pounds  per  square  foot,  and  the  2^-inch  floor,  5 
feet  span,  150  pounds  per  square  foot,  with  factor  of  safety  of  four, 
and  the  published  tests  that  have  been  made  of  this  system  would 


Air  Space. 


Iron  Tie. 


Fig.  195. 


appear  to  sustain  the  guarantee.  This  construction  appears  to  be 
especially  strong  to  resist  drop  or  jarring  loads.  A  ram  weighing  238 
pounds  was  dropped  from  the  height  of  8  feet  on  the  dentre  of  an 
8-foot  span  several  times  without  perceptible  effect  on  the  floor.  (The 
bars  in  this  floor  were  2\  inches,  spaced  20  inches  apart.)  It  is  also 
claimed  that  in  case  of  overloading  the  floor  will  not  fail  suddenly, 
but  that  the  bars  will  gradually  bend,  thus  giving  warning  of  danger. 

The  complete  fireproof  quality  of  this  floor,  which  is,  of  course, 
the  same  as  that  of  the  Roebling  and  other  Portland  cement  floors, 
was  proved  by  a  severe  test  of  fire  and  water  while  the  floor  was  uni- 
formly loaded  with  750  pounds  per  square  foot. 

Economy. — While  this  floor  is  thoroughly  fireproof  and  waterproof 
and  possesses  ample  strength  and  remarkable  rigidity,  it  also  possesses 
several  advantages  of  a  practical  and  economical  nature. 


290 


BUILDING  CONSTRUCTION. 


No  tie-rods  are  required,  and  no  punching  of  the  I-beams  is  nec- 
essary, except  where  they  are  framed  to  the  girders  or  around  open- 
ings. Lighter  beams  may  be  employed  than  where  heavier  types  of 
floor  construction  are  used.  No  channels  are  required  in  outside 
masonry  walls. 

In  buildings  having  brick  partitions  and  solid  masonry  walls  this 
floor,  with  paneled  ceiling,  is  especially  economical,  as  no  channels 
are  required,  and  the  beams  require  no  punching,  except  for  anchor- 
ing their  ends  to  the  walls.  This  floor  can  be  constructed  as  rapidly 
as  any  and  can  be  carried  out  without  difficulty  in  winter  weather. 

Holes  may  be  cut  at  anyplace  in  the  floor  by  plumbers  or  electric- 
ians without  injuring  the  strength  of  the  floor,  and  the  holes  may  be 
cut  as  small  or  as  large  as  may  be  necessary. 

312.  Actual  Weight  of  Fireproof  Floors.— In  the  spring 
of  1895  a  series  of  fireproofing  tests  was  made  in  the  basement  and 
first  story  of  a  building  then  being  erected  in  Boston,  a  full  descrip- 
tion of  which  may  be  found  in  the  American  Architect  of  Septem- 
ber 7,  1895. 

The  question  of  the  comparative  weights  of  the  different  floor  con- 
struction having  been  raised,  it  was  decided  to  weigh  a  section  of  each. 

The  debris  from  the  fires  was  removed  from  the  houses,  the  floors 
broken  down,  care  being  taken  to  preserve  all  the  material  that  had 
entered  into  their  construction,  and  it  was  then  weighed  on  platform 
scales.  The  data  thus  gathered  are  tabulated  below  : 


TEST  NO. 

CONSTRUCTION. 

AREA  OF 
SECTION. 

TOTAL 
WEIGHT. 

WEIGHT  PER 
SQ.   FT. 

I. 

1  8    sq    ft 

I  295  Ibs 

72      Ibs 

2. 

Metropolitan  System,  panel 
construction  

18 

427     " 

23.7     " 

3- 

Expanded  Metal  Co.'s  Sys- 
tem   

22.5     " 

I  697     " 

75-4     " 

3* 

Same  as  No.  3,  with  addi- 
tional flat  ceiling  

22.5     " 

1,814     " 

80.6     " 

4. 

Eureka  System 

I  648     " 

81  -\     " 

5- 

12-inch  porous  hollow  tile 
arch  blocks  covered  with 
concrete  2  inches  thick.  . 

20.25  " 

1,781     " 

87-95  " 

In  considering  this  table  it  should  be  noted  that  all  of  the  floors, 
with  the  exception  of  No.  2,  were  plastered  on  the  under  side,  and  were 


FIREPROOFING.  291 

concreted  on  top,  ready  to  receive  the  wood  floors.  The  plastering 
on  No.  5  fell  during  the  fire  test  and  was  removed  with  the  debris, 
and,  consequently,  not  weighed  with  the  other  material ;  the  weight 
of  the  1 2 -inch  floor  beams  is  not  included  in  the  weight  given  above. 

313.  Selection  of  a  System. — Where  there  are  so  many  styles 
of  fireproof  floors,  each  claiming  to  be  superior  to  the  others,  it  is  dif- 
ficult for  the  architect  to  decide  on  a  particular  construction.  The 
choice  of  a  system  of  fireproofing  is  more  apt  to  be  decided  by  the 
question  of  cost  than  by  other  considerations.  The  relative  cost  of 
different  systems  will  also  vary  somewhat  with  the  locality  and  dis- 
tance from  the  manufacturing  centres.  It  should  be  ascertained, 
before  fully  deciding  on  the  system  to  be  used,  by  obtaining  approx- 
imate bids  from  the  different  fireproofing  companies,  most  of  whom 
are  always  ready  to  submit  such  bids. 

The  author  believes  that  either  of  the  floor  systems  described 
herein,  if  properly  constructed  with  materials  of  good  quality,  will 
make  a  thoroughly  fireproof  floor,  although  where  the  danger  from  a 
severe  conflagration  is  especially  imminent,  porous  tiling  is  generally 
considered  as  the  superior  non-conducting  material. 

The  question  of  strength  hardly  needs  to  be  considered  except  for 
floors  for  warehouses  and  heavy  storage  buildings,  as  either  of  the 
systems  possess  sufficient  strength  for  other  buildings  if  the  sections 
are  not  made  too  light  or  the  spans  too  great. 

Where  heavy  loads  are  to  be  carried,  however,  those  systems  which 
have  uniformly  developed  the  greatest  strength  should  be  selected. 
The  question  of  lightness  is  often  one  of  considerable  importance, 
especially  in  dwellings,  apartment  houses,  hotels  and  office  buildings. 
Very  often  the  considerations  of  speed  in  erection  and  quickness  in 
drying  out,  the  adaptability  to  putting  in  place  in  cold  weather,  etc., 
are  sufficient  to  decide  in  favor  of  a  particular  system. 

Many  engineers  still  favor  the  use  of  dense  or  porous  tiles  for  fire- 
proofing,  and  these  materials  are  undoubtedly  of  great  value,  and 
possibly  the  best  for  certain  conditions,  but  the  combinations  of  iron 
with  Portland  cement  concrete  are  rapidly  gaining  in  favor,  and  the 
author  believes  that  concrete,  when  properly  combined  with  the 
metal,  makes  a  very  strong  and  thoroughly  fireproof  construction, 
and  that  it  has  now  been  used  for  a  sufficient  length  of  time  to  fully 
demonstrate  its  adaptability  to  floor  construction. 

With  nearly  all  systems  of  fireproofing  the  efficiency  of  the  con- 
struction depends  very  largely  upon  the  character  of  the  workman- 


292  BUILDING  CONSTRUCTION. 

ship  and  the  quality  of  the  materials  used.  When  it  is  desirable  to 
use  as  much  unskilled  labor  as  possible,  the  Fawcett,  Roebling  or 
Columbian  floors  can  be  used  to  advantage,  an  intelligent  and  honest 
foreman  being  the  only  skilled  person  required. 

FIREPROOF  ROOFS. 

314.  Flat  Roofs. — Nearly  all  fireproof  office  buildings,  apart- 
ment houses,  hotels  and  warehouses  have  "  flat "  roofs,  pitched  just 
enough — generally  from  £  to  \  an  inch  to  the  foot — to  cause  the  water 
to  run  to  the  lowest  point.  It  is  easier  to  make  a  flat  roof  thoroughly 
fireproof  than  it  is  a  pitch  roof,  and  the  flat  roof  is  also  much  less 
expensive. 

The  usual,  and  also  the  best,  method  of  constructing  flat  roofs  on 
fireproof  buildings  is  to  build  the  roof  in  the  same  way  as  the  floors, 
giving  the  beams  the  same  pitch  as  the  roof.  If  the  filling  between 
the  beams  is  of  hollow  tile,  segmental  arches,  or  flat  arches  with  raised 
skewbacks,  may  be  used  with  economy. 

When  a.ny  of  the  patented  systems  of  fireproof  construction  is  used, 
the  roof,  if  flat,  is  almost  invariably  constructed  in  the  same  way  as 
the  floor,  only  using  a  little  lighter  section. 

After  the  filling  between  the  beams  is  set,  the  roof  should  be  cov- 
ered with  cement  mortar  or  concrete,  sufficient  to  bring  it  to  a  uni- 
form surface  and  to  give  the  desired  pitch. 

The  roofing  may  be  either  of  tin,  copper,  rock  asphalt  or  compo- 
sition, finished  on  top  with  gravel  or  vitrified  tile  set  in  Portland 
cement.  Coal  tar,  pitch  and  asphalt  have  a  natural  affinity  for 
cement  or  terra  cotta,  and  adhere  readily  to  them  without  the  use  of 
fastenings.  If  a  tin  or  copper  covering  is  to  be  used,  porous  tiling  is 
especially  adapted  for  the  beam  filling,  as  the  nails  for  the  tin  cleats 
may  be  driven  directly  into  the  tiling.  Before  applying  the  tin  the 
entire  surface  of  the  roof  should  be  plastered  smooth  with  £  of  an 
inch  of  cement  mortar  to  form  a  smooth,  hard  surface  on  which  to 
hammer  down  the  tin.  Thin,  hollow  tiles,  set  between  3X3-inch 
T-irons,  are  also  occasionally  used  for  roofs. 

Whatever  kind  of  tiling  or  filling  is  used  it  should  be  of  such  con- 
struction that  the  bottom  flanges  of  the  beams  or  T-irons  will  be  well 
protected,  and  if  tiling  is  used  it  should  receive  a  heavy  coat  of  plas- 
ter under  the  beams,  if  not  elsewhere.  The  supporting  girders  and 
columns  should  also  be  well  protected,  either  with  hollow  tiles,  con- 
crete or  plastering  on  metal  lathing. 


fIREPROOFING.  293 

315.  Mansard  and  Pitch  Roofs. — For  mansard  roofs  the  most 
economical  method  of  construction  is  by  using  I-beams,  set  5  to  7  feet 
apart,  and  filled  in  between  with  3-inch  hollow  partition  tile,  provis- 
ion for  nailing  slate  being  made  by  attaching  i£x2-inch  wood  strips 
to  the  outer  face  of  the  tile,  the  strips  being  set  at  the  proper  distances 
apart  to  receive  the  slate,  the  spaces  between  the  strips  being  then 
plastered  flush  and  smooth  with  cement  mortar.     In  case  of  a  severe 
conflagration  the  slate  would  probably  be  destroyed,  and  the  wooden 
strips  might  be  consumed,  but  the  damage  could  go  no  farther.     In 
place  of  partition  tile  porous  terra  cotta  bricks  or  blocks  may  be  used 
for  filling  between  the  I-beams.     For  roofs  where  the  pitch  is  not 
over  45°,  3X3-inch  T-irons,  set  16  inches  between  centres  and  filled  in 
with  slabs  of  porous  terra  cotta,  make  a  very  desirable  roof.     If  slates 
or  roofing  tiles  are  used  they  may  be  nailed  directly  into  the  porous 
tiles,  or,  if  it  is  desired  to  use  hollow  tile,  strips  of  wood  may  be 
nailed  to  the  tile  for  receiving  the  slate  and  the  spaces  between  the 
strips  filled  in  with  cement. 

All  truss  members,  purlines,  etc.,  should  be  protected  from  fire  and 
heat  either  by  wire  lathing  or  by  porous  tiling,  covered  with  a  heavy 
coat  of  plaster.  Probably  the  best  and  most  thorough  method  of 
protecting  truss  members  is  by  first  covering  them  with  i^-inch  slabs 
of  porous  tiling  and  wrapping  them  securely  with  stiffened  wire  lath- 
ing, which  should  then  be  covered  with  a  heavy  coat  of  cement  plaster. 

316.  Ceilings. — In  office  buildings  having  a  flat  roof  there  is  gen- 
erally an  air  space  or  attic  between  the  roof  and  ceiling  of  the  upper 
story,  varying  from  3  to  5  feet  in  height.     This  space  is  often  utilized 
for  running  pipes,  wires,  etc.     Buildings  having  pitched  roofs  neces- 
sarily require  a  ceiling  below  to  give  a  proper  finish  to  the  rooms 
in  the  upper-  story  and  to  make  the  rooms  comfortable.     In  office 
buildings  the  ceiling  under  the  roof  is  generally  of  a  similar  construc- 
tion to  that  of  the  floors,  although  when  systems  like  the  Roebling, 
Columbian  or  Metropolitan  are  used  in  the  building  only  the  sus- 
pended ceiling  plate  is  required  between  the  beams,  and  the  latter 
may  be  made  very  light. 

Under  pitch  roofs  (and  sometimes  under  flat  roofs)  a  suspended 
ceiling  is  generally  used.  T-bars  (usually  3x3  inches  in  size)  are  hung 
from  the  roof  construction  by  means  of  light  rods,  and  the  ceiling 
constructed  either  by  means  of  wire  or  expanded  metal  lathing  laced 
to  light  angles,  or  flat  bars  placed  between  the  T's,  or  by  thin  tiles  of 
dense  or  porous  terra  cotta.  If  a  tile  ceiling  is  to  be  used,  the  author 
believes  that  porous  or  semi-porous  terra  cotta  should  be  given  the 


294  BUILDING  CONSTRUCTION. 

preference.  Whichever  material  is  used,  the  shape  of  the  tiles  should 
be  such  that  they  will  drop  below  the  flanges  of  the  T's,  so  as  to  pro- 
tect the  metal. 

Fig.  196  shows  the  usual  section  of  porous  ceiling  tile,  and  Fig.  197 
an  improved  shape  of  semi-porous  ceiling  tile  made  by  the  Pioneer 
Co.  The  width  of  the  porous  tile  is  16  inches  for  2 -inch  tile  and  18, 
20  and  24  inches  for  3-inch  tile.  The  2-inch  tiles  weigh  n  pounds 


Fig.  196. 

and  the  3-inch  tiles  15  pounds  per  square  foot,  exclusive  of  the  plas- 
tering. The  tiles  shown  in  Fig.  197  are  3  inches  thick  and  weigh 
14^  pounds  per  square  foot. 

Suspended  ceilings  of  wire  lath  and  plaster  weigh  only  about  12 
pounds  per  square  foot,  including  the  plastering. 

Whether  tile  or  metal  lathing  is  used  for  the  ceiling,  the  webs  of 
the  T's  should  be  covered  with  plaster  or  cinder  concrete,  to  protect 
them  from  heat. 

317.  Girder  and  Column  Casing's.  —  The  columns  and  gird- 
ers are  more  exposed  to  intense  heat  than  the  floor  beams,  and  should 
be  protected  in  the  most  efficient  manner  possible,  as  any  expansion 
in  the  columns  or  girders  would  have  a  most  disastrous  effect. 


/\  _________  ,,,,,,,,,,,,&,,,,,^,,,f,.,,,,,,,,,fiL  " 


Fig.  ,97. 

Columns  and  girders  are  also  more  exposed  to  the  streams  of  water, 
which  tend  to  dislodge  or  break  through  the  casing.  As  a  rule,  the 
manner  in  which  these  portions  of  the  structural  work  are  protected 
depends  largely  upon  the  system  of  floor  construction  employed. 
Naturally  the  parties  having  the  contract  for  the  fireproofing  of  the 
floors  generally  wish  to  use  their  system,  or  materials,  for  protecting 
the  columns  and  girders,  and  thus  the  question  of  cost  often  works  to 
the  disadvantage  of  the  better  system. 

In  buildings  with  tile  filling  between  the  floor  beams  the  columns 
and  girders  are  usually  cased  with  tiles  ;  when  one  of  the  concrete 


FIREPROOFING. 


295 


systems  of  floor  construction  is  adopted,  the  same  material  is,  as  a 
rule,  employed  for  protecting  these  members,  although  there  is  no 
necessity  for  using  the  same  material  in  both  cases. 

The  unbiased  opinion  of  architectural  engineers  and  those  who 
have  made  a  study  of  fire  protection  is,  the  author  believes,  in  favor 
of  solid  porous  tiling  for  girder  and  column  casings.  The  author 
believes  that  the  best  possible  protection  for  these  members  will  be 
obtained  by  using  solid  blocks  of  porous  terra  cotta,  well  secured  to 
the  metal,  and  then  covered  with  wire  or  expanded  metal  lathing 
plastered  with  hard  mortar,  such  as  "Acme"  or  "  King's  Windsor," 
the  metal  lathing  serving  principally  as  a  protection  from  the  blocks 
becoming  dislodged. 

Girders. — The  usual  forms  of  dense  or  porous  tile  casings  for  gird- 
ers are  shown  in  Fig.  198.  Shapes  very  similar  to  these  are  made  by 


Fig.  198. 

all  the  manufacturers  of  both  dense  and  porous  tiling.  Casings  of 
dense  tiling  should  preferably  be  made  hollow,  thus  giving  a  second 
air  space,  as  shown  in  Fig.  195,  JB.  Methods  of  casing  girders  with 
metal  lathing  will  be  shown  in  Chapter  XL 

318.  Columns. — The  protection  of  the  columns,  especially  in  a 
very  high  building,  should  be  considered  as  the  most  important  por- 
tion of  the  fireproofing,  although  in  too  many  cases  it  is  slighted  even 
to  a  dangerous  extent.  The  Chicago  building  ordinance  is  quite 
explicit  in  its  requirements  for  the  protection  of  columns,  and  forms 
a  good  guide  for  architects  elsewhere  to  follow.  These  requirements 
are  as  follows  : 

SEC.  108.  In  the  case  of  buildings  of  Class  I.  the  coverings  for  columns  shall  be, 
if  of  brick,  not  less  than  8  inches  thick  ;  if  of  hollow  tile,  these  coverings  shall  be  in 
two  consecutive  layers,  each  not  less  than  i\  inches  thick.  If  the  fireproof  covering 
is  made  of  porous  terra  cotta,  it  shall  consist  of  at  least  two  layers  not  less  than  2 
inches  thick  each.  Whether  hollow  tile  or  porous  terra  cotta  is  used,  the  two  con- 
secutive layers  shall  be  so  applied  that  neither  the  vertical  nor  the  horizontal  joints 


BUILDING  CONSTRUCTION. 


'2'PorousTile 


in  the  same  shall  be  opposite  each  other,  and  each  course  shall  be  so  anchored  and 
bonded  within  itself  as  to  form  an  independent  and  stable  structure. 

SEC.  109.  In  places  where  there  is  trucking  or  wheeling  6r  other  handling  of 
packages  of  any  kind,  the  lower  5  feet  of  the  fireproofing  of  such  pillars  shall  be 
encased  in  a  protective  covering  either  of  sheet  iron  or  oak  plank,  which  covering 
shall  be  kept  continually  in  good  repair. 

SEC.  in.  In  buildings  belonging  to  Class  II.  the  fireproof  covering  for  internal 
columns  is  to  be  made  the  same  as  specified  for  the  buildings  of  Classes  I.  and  IV., 
excepting  only  that  but  one  covering  of  hollow  tile  or  porous  terra  cotta,  and  but 
two  layers  of  any  covering  made  of  plastering  on  metallic  lath,  are  to  be  used. 

The  most  common  and  cheapest  method  of  fireproofing  interior 
columns  has  been  through  the  use  of  shells  of  dense  terra  cotta  sur- 
rounding the  column,  the  separate  tiles  being  usually  clamped  or 

hooked  together,  but  not  to  the 
metal  work.  This  method  has 
not  proved  altogether  successful. 
"  The  use  of  dense  tiles  is  only 
to  be  recommended  when  such 
tiles  are  hollow,  with  a  proper 
air  space  around  the  metal  col- 
umn, and  even  then  experience 
seems  to  show  that  the  hard  tile 
is  in  no  way  as  satisfactory  under 
great  heat  as  the  more  porous 
kinds."* 

Solid  blocks  of  porous  tiling  at 

least  2  inches  thick,  well  bedded  against  the  metal  column  and 
secured  by  copper  wire  wound  around  the  column  outside  of  the  cas- 
ing, seems  to  be  the  most  approved  method  of  insulation. 

The  custom  has  been  quite  general  of  running  the  water  and  gas 
pipes  beside  the  metal  columns  and  inside  the  fireproof  casing. 
When  this  is  done  the  protection  at  the  floors  is  often  very  imper- 
fectly made,  and  the  custom  is  not  now  approved. 

The  best  method  of  running  and  concealing  the  pipes  is  that  shown 
in  Fig.  199,  which  represents  the  fireproofing  of  the  columns  in  the 
first  eight  stories  of  the  newer  portion  of  the  Monadnock  Building  in 
Chicago. 

Fig.  200  shows  a  few  of  the  best  shapes  of  dense  tile  covering. 
The  tile  shown  at  A  may  be  used  for  any  size  or  shape  (except 
round)  of  column  by  varying  the  width  of  filling  pieces  a. 

*  Joseph  K.  Freitag,  C   E.,  in  Architectural  Engineering. 


Hollo wBrick  in  cement 


FIREPROOFING. 


297 


Columns  are  also  occasionally  protected  by  surrounding  them  with 
a  thick  coating  of  concrete.  When  the  concrete  is  formed  in  place 
so  as  to  make  a  monolithic  shell,  extending  3  or  4  inches  beyond  the 
metal,  this  should  make  a  very  efficient  protection. 

Methods  of  protecting  columns  by  metal  lathing  and  plaster  are 
described  in  Chapter  XI. 

319.  Partitions. — The  partitions  in  fireproof  buildings  should  be 
built  either  of  brick,  tile  or  iron  studding,  covered  with  metal  lath 
and  plaster.  Brick  partitions,  when  not  less  than  12  inches  thick, 
may  be  considered  as  fireproof,  but  they  are  now  seldom  used  except 
where  they  can  be  utilized  to  support  the  floors. 

In  the  modern  fireproof  office  building,  hotel  or  apartment  house 
the  floors  are  supported,  except  at  the  walls,  entirely  by  columns  and 
girders,  and  the  partitions  are  almost  universally  constructed  either 


Fig.  200. 

of  hollow  tile,  or  of  thin,  solid  porous  tiles,  or  metal  lath  and  plaster. 
Hollow  tile  are  probably  the  most  extensively  used  for  this  purpose, 
although  "thin"  partitions  (from  i^  to  2  inches  thick)  are  coming 
into  quite  general  use  in  office  buildings. 

Partition  tiles  are  made  of  the  same  materials  and  possess  the  same 
characteristics  as  those  used  in  floor  construction.  Both  dense  and 
porous  tiles  are  used  for  this  purpose,  porous  tiles  probably  the  most 
extensively,  owing  to  their  property  of  receiving  and  holding  nails. 

Partition  tiles  are  made  in  thicknesses  varying  from  2  to  6  inches,  but 
the  4-inch  blocks  are  most  commonly  used.  The  tiles  are  generally 
12x12  or  6x12  inches  on  the  face.  They  may  be  set  with  the  hollows 
running  vertically  or  horizontally,  either  construction  being  sufficiently 
strong  ;  the  horizontal  construction,  however,  has  the  advantage  of  a 
better  bonded  mortar  joint.  When  the  tiles  are  laid  vertically  they 
are  frequently  clamped  together  ;  when  laid  horizontally  a  certain 


298 


BUILDING  CONSTRUCTION. 


number  of  tile  should  be  set  vertically  to  accommodate  the  gas  pipes. 
When  the  latter  are  located  before  the  partitions  are  set  the  tile  may 
be  cut  and  built  around  the  pipes,  or  special  recessed  tile  may  be 
used,  as  shown  in  Fig.  201.  Whether  laid  vertically  or  horizontally,  the 
blocks  should  always  be  set  so  as  to  break  joint  with  each  other. 

For  setting  the  tiles  or  blocks, 
lime  mortar,  to  which  a  small 
proportion  of  natural  cement  is 
added,  is  generally  used.  Acme 
cement  plaster  has  recently 
been  used  for  this  purpose  with 
excellent  results,  as  it  adheres 
to  the  tiling  even  better  than 
natural  cements. 

At  all  openings  in  partitions 
rough  wood  frames  are  set,  as 


shown  in  Fig.  202,  to  stiffen  the 
jambs  and  to  afford  grounds  for 
the  plaster  and  nailings  for  the 
G&5  |  I  P6.      finished  frames  and  casings. 

If  dense  tiles  are  used  for  the 

Fig<  2oi  partitions    it    is    necessary    tc 

build     in    wooden     bricks    or 

|-inch  strips  in  the  horizontal  or  vertical  joints  to  form  nailings  for 
the  base,  chair  rail  and  picture  moulding,  or  courses  of  porous  tiles 
may  be  inserted  at  these  places.  Wrhen  porous  tiles  are  used  the 
wood  blocks  or  strips  are  generally  omitted,  although  experience  has 
shown  that  porous  tiles  do  not  hold  the  nails  quite  so  securely  as  wood. 

Hollow  tile  partitions  are  generally 
laid  on  top  of  the  finished  floor  if  there 
is  the  least  likelihood  of  their  ever 
being  taken  down,  and,  as  they  are  not 
fastened  in  any  way  to  the  floor  or  ceil- 
ing, they  can  very  easily  be  removed  or 
changed  to  suit  tenants. 

The  weight  of  hollow  tile  partitions  per  square  foot,  plastered  both 
sides,  will  average  as  follows  : 


3-inch  dense  tile 27  pounds. 

4-inch  dense  tile 29  pounds. 

f-inch  dense  tile 32  pounds. 

(.-inch  dense  tile 36  pounds. 


3-inch  porous  tile. ....  .24  pounds. 

4-inch  porous  tile 29  pounds. 

5-inch  porous  tile 35  pounds. 

6-inch  porous  tile 39  pounds. 


FIREPROOFING.  299 

320.  Thin  Partitions. — In  order  to  economize  the  floor  space 
.s  much  as  possible,  devices  have  been  introduced  for  constructing 
artitions  that,  when  plastered  both  sides,  will  be  only  from  \\  to  2f 
iches   thick.      Such    partitions   are  now   commonly  designated  as 
thin  "  partitions.     There  are  a  number  of  devices  for  constructing 

ciiin  partitions,  nearly  all  of  them  using  i^-inch  steel  studding,  to 
which  expanded  metal  or  wire  lathing  is  applied,  and  sometimes  bur- 
lap. These  constructions  are  generally  erected  by  the  plasterer,  and 
will  be  described  in  Chapter  XL 

Henry  Maurer  &  Son  have  patented  a  partition  made  of  2- inch 
blocks  of  solid  porous  terra  cotta,  each  block  being  connected  to  the 
other  by  a  galvanized  iron  clamp.  The  bottom  and  top  courses  are 
also  secured  to  the  floor  and  ceiling  by  means  of  a  galvanized  iron 
shoe.  No  other  supports  in  the  shape  of  ironwork  are  necessary,  and 
it  is  claimed  that  the  partition  is  very  stiff.  The  blocks  can  be  put 
up  by  either  carpenter  or  mason.  The  thickness  of  the  partition, 
when  plastered  both  sides,  is  3  inches,  and  the  weight  per  square  foot, 
including  plastering,  20  pounds. 

The  Lee  Construction  Co.  also  have  a  patented  thin  partition,  which 
is  made  of  exceedingly  light  and  porous  plates  of  porous  tiling,  with 
tension  rods  of  twisted  steel  wires  placed  on  each  side  and  imbedded 
in  the  plaster.  No  studding  is  used.  The  tension  rods,  being  on  the 
outside  of  the  partition,  make  the  partition  very  stiff  and  perfectly 
straight.  This  partition  is  made  by  the  Lee  Co.  and  plastered  one 
•coat  with  hard-setting  plaster,  such  as  "  Acme  "  or  "  Windsor,"  so 
that  only  the  finishing  coat  of  plaster  need  be  applied  by  the  plas- 
terer. The  Lee  Co.  also  supply  and  set  the  rough  frames  for  doors 
and  side  lights,  and  build  in  all  nailing  blocks  for  the  base,  chair  rail 
and  picture  mould.  The  thickness  of  this  partition  when  finished  is 
2  inches  for  stories  13  feet  high,  2\  inches  for  stories  from  13  to  15 
feet,  3  inches  for  stories  15  to  18  feet  and  4  inches  for  stories  20  feet 
high.  This  partition  was  used  throughout  the  fifteen-story  Syndicate 
Building  in  New  York  City. 

321.  Wall  Furrings. — It  is  generally  customary  to  fur  the  base- 
ment walls  of  fireproof  buildings,  and  occasionally  the  walls  above, 
with  tile  blocks  made  for  this  purpose. 

The  most  common  shape  of  furring  tile  is  that  shown  in  Fig.  203, 
the  blocks  being  12  inches  square  and  2  inches  thick,  although  fur- 
ring tile  are  made  i£  inches  thick,  and  in  both  larger  and  smaller 
sizes.  They  are  also  made  of  both  dense  and  porous  tiling.  The 
latter  possesses  the  advantage  that  nailing  strips  are  not  required, 


3oo 


B  UILD1NG  CONS TR  UCT2  ON. 


but  it  is  doubtful  if  they  offer  as  good  protection  from  moisture  as 
the  harder  burned  fire  clay  tiles. 

The  tiles  are  laid  against  the  walls  in  ordinary  lime  and  cement 
mortar,  with  broken  joints,  the  hollows  always  running  vertically. 


Kig.  203. 


Flat-headed  nails  are  driven  at  the  joints  into  the  brickwork  to 
secure  the  tiles  until  the  mortar  has  set.  When  dense  furring  tile  are 
used,  £-inch  strips  of  wood  should  be  laid  in  the  joints,  either  vertical 


amp. 


Fig.  204. 


or  horizontal,  to  receive  the  grounds  or  wood  finish.     Three-inch 
hollow  partition  blocks  are  also  sometimes  used  for  furring. 

Fig.  204  shows  a  good  method  of  furring  the  walls  of  rooms  used 
for  cold  storage,  etc. 


CHAPTER  X. 

IRON  AND  STEEL  SUPPORTS  FOR   MASON 
WORK.— SKELETON  CONSTRUCTION. 


322.  Although  constructions  of  iron  and  steel  do  not  properly  come 
within  the  scope  of  this  volume,  there  are  so  many  places  where 
metal  work  is  used  in  connection  with  brick,  stone  and  terra  cotta 
that  it  has  been  thought  desirable  to  briefly  describe  the  most  com- 
mon forms  of  iron  and  steel  construction  used  for  supporting  masonry 
walls,  and  the  various  minor  details  of  metal  work  used  in  connection 
with  the  mason  work. 

Girders  and  Lintels. — All  openings  in  masonry  walls  which  it 
is  not  feasible  to  span  with  arches  should  have  iron  or  steel  lintels  or 
girders  to  support  the  mason  work  above.  The  objections  to  wooden 
beams  for  supporting  mason  work  are  given  in  Section  255. 

Since  the  price  of  rolled  steel  has  been  so  greatly  reduced,  girders 
and  lintels  for  supporting  brick  and  stone  walls  are  almost  univer- 
sally formed  of  steel  I-beams,  or  girders  built  up  of  steel  plates  and 
angle  bars.  Except  for  very  wide  spans  and  exceptionally  heavy 
loads,  steel  I-beams  may  be  most  economically  used  for  such  sup- 
ports. As  a  rule,  at  least  two  beams  should  be  used  to  support  a 
9-inch  or  1 2-inch  wall,  and  three  beams  for  a  1 6-inch  wall,  the  size  of 
the  beams,  of  course,  depending  upon  the  weight  to  be  supported.  The 
beams  should  be  connected  at  their  ends,  and  every  4  or  5  feet 
between  with  bolts  and  cast  iron  separators,  cast  so  as  to  exactly  fit 
between  the  beams.  The  girders  should  have  a  bearing  at  each  end 
of  at  least  6  inches,  and  should  also  rest  on  cast  iron  bearing  plates 
of  ample  size. 

If  the  wall  to  be  supported  is  of  brick,  the  first  course  above  the 
girder  should  be  laid  all  headers.  The  width  of  the  girder  is  gener- 
ally made  2  inches  less  than  that  of  the  wall.  In  calculating  the 
weight  to  be  supported  by  a  girder,  much  depends  upon  the  structure 
of  the  wall  above.  If  the  wall  is  without  openings,  and  does  not  sup- 
port floor  beams,  only  the  portion  of  the  wall  included  within  the 


302 


BUILDING  CONSTRUCTION. 


dotted  lines,  Fig.  205,  need  be  considered  as  being  supported  by  the 
girder.  The  beams  in  that  case,  however,  should  be  made  very  stiff, 
so  as  to  have  little  deflection.  If  there  are  several  openings  above  the 
girder,  and  especially  if  there  be  a  pier  over  the  centre  of  the  girder, 

B 


B 


Fig.  206. 


II 


as  shown  in  Fig.  206,  then  the  man- 
ner in  which  the  weight  bears  on 
the  girder  should  be  carefully  con- 
sidered. In  a  case  such  as  is  shown 
in  Fig.  206  the  entire  dead  weight 
included  between  the  dotted  lines 
A  A  and  B  B  should  be  consid- 
ered as  coming  on  the  girder,  and 
proper  allowance  made  for  the  load  being  mostly  concentrated  at  the 
centre. 

Steel  lintels  for  supporting  stone  or  terra  cotta  caps  and  flat  arches 
are  described  in  Section  190. 

323.  Cast  Iron  Lintels.— Lintels  of  cast  iron  were  at  one  time 
extensively  used  for  supporting  brick  walls  over  store  fronts  and  door 
openings,  and  even  at  the  present  time  are  used  to  some  extent.  On 
account  of  the  brittle  character  of  this  metal,  however,  and  its  low 
tensile  strength,  it  should  not  be  used  for  beams  subjected  to  a  moving 
load,  such  as  floors  upon  which  heavy  articles  are  moved. 

Cast  iron  beams  of  long  span  are  also  not  as  economical  as  those 
made  of  rolled  steel.  About  the  only  places,  therefore,  in  which  cast 
iron  lintels  may  be  suitably  and  economically  used,  are  over  store 
fronts  where  the  span  does  not  exceed  8  feet,  and  over  door  openings 
in  unfinished  brick  partitions  where  a  flat  head  is  necessary.  The 


IRON  SUPPORTS  FOR  MASON  WORK. 


3°3 


relative  economy  between  cast  iron  and  steel  lintels  will  depend 
largely  upon  the  distance  from  the  rolling  mills  and  upon  freight  rates. 
Foundries  for  casting  iron  are  much  more  widely  distributed  than 
rolling  mills,  so  that  castings  of  almost  any  shape  can  usually  be 
obtained  in  any  city  of  twenty  thousand  inhabitants,  while  mills  for 
rolling  steel  beams  are  comparatively  few  in  number  and  located 
mostly  in  the  extreme  eastern  portion  of  the  country. 

The  common  shape  for  cast  lintels  over  door  openings  is  that  shown 


Fig.  207. 


Fig. 


in  Fig.  207.  The  width  of  the  flange  is  usually  made  the  full  thick- 
ness of  the  wall,  and  the  extreme  height  of  the  lintel  at  the  centre 
not  less  than  two-thirds  nor  greater  than  the  width  of  the  flange.  The 
strength  of  the  lintel  may  be  somewhat  increased  by  stiffening  the 
web  at  the  centre  by  brackets,  as  shown  by  dotted  lines  at  A. 

Where  the  width  of  the  flange  must  be  over  16  inches  two  webs 
should  be  used,  as  shown  by  the  section  drawing,  Fig.  208.  For 
handling  and  moulding  it  is  best  not  to  make  the  flange  more  than 
24  inches  wide;  if  a  greater  width  than  this  is  required,  several  lintels 


Fig.  209. 

should  be  placed  side  by  side.  The  thickness  of  the  metal  should  not 
be  less  than  f  inch,  and  the  web  should  be  about  \  inch  thicker  than 
the 'flange. 


304 


BUILDING  CONSTRUCTION. 


When  proportioned  as  above  the  strength  of  the  lintel  to  support  a 
dead  load  may  be  safely  made  equal  to 

9700  X    area  of  bottom  flange  X  extreme  depth 
span  in  inches. 


— Store  Front  Lintel. 


Thus  a  lintel  of  6  feet  clear  span  with  1 2-inch  by  f-inch  flange  and 
extreme  depth  of  12  inches  should  safely  support 


9700  X  9  X  12 
72 


=    14,550  pounds. 

Lintels  over  store  fronts  should 
be  made  with  ribs  at  the  ends,  as 
shown  in  Fig.  209,  with  holes  for 
bolting  the  lintels  to  each  other 
and  to  columns.  Store  front  lin- 
tels are  also  occasionally  made  as 
shown  in  Fig.  210,  to  give  a  finish 
above  the  openings. 

Fig.  211  shows  details  for  cast 
iron  lintel  and  sill,  sometimes  used 
for  windows  in  external  walls.  The 
thickness  of  the  metal  need  not 
exceed  f  of  an  inch. 
324.  Cast  Iron  Arch  Girders  are  also  sometimes  used  to  sup- 
port brick  and  stone  walls  where  the  opening  is  from  10  to  30  feet 
in  width.  Fig.  212  shows  a  girder  of  this  kind  that  was  used  to  sup- 
port a  central  tower  over  the  crossing  of  the  nave  and  transept  on 
St.  John's  Church,  Stockton,  California,  Mr.  A.  Page  Brown,  archi- 
tect. The  clear  span  is  29^  feet,  and  the  height  of  the  wall  above 
the  girder  18  feet.  One  object  in  using  such  a  girder  in  this  place 
was  to  get  the  height  in  the  centre  without  also  raising  the  supports, 


Pig. 


IRON  SUPPORTS  FOR  MASON  WORK. 


3<>5 


which  could  not  be  obtained  with  a  steel  plate  girder.  The  church 
has  a  vaulted  ceiling  which  comes  just  below  the  arch  of  the  girder, 
the  tie-rod  being  exposed. 


Section  at  Center 


Fig.  2  is. 


The  rise  of  the  casting  in  this  case  is  rather  more  than  common, 
the  usual  rise  being  from  yV  to  \  of  the  span.  The  end  of  the  girder 
is  generally  cast  in  the  shape  of  a  hollow  box,  with  shoulders  to 
receive  the  ends  of  the  rods.  The  tie-rod  is  often  made  with  square 
ends,  and  about  \  inch  shorter  than  the  casting,  and  is  heated  until 
the  expansion  permits  of  its  being  slipped  into  its  place  in  the  cast- 
ing. As  it  cools  the  contraction  binds  it  tightly  into  its  place.  If 
tightened  by  means  of  a  screw  and  nut,  the  nut  and  bearings  should 
be  dressed  to  a  smooth  surface  and  the  rod  turned  up  with  a  long- 
handled  wrench.  It  is  very  essential 
that  the  rod  shall  be  fitted  in  place  so 
tightly  that  no  tensile  strain  can  come 
on  the  casting,  and,  on  the  other  hand, 
it  should  not  be  expanded  so  as  to 
bring  an  initial  strain  on  the  arch. 

This  form  of  girder  is  comparatively 
little  used  now,  but  there  may  be  con- 
ditions, as  in  the  church  mentioned 
above,  where  it  can  be  used  to  advan- 
tage. 

325.  Supports  for  Bay  Win- 
dows.— Where  bay  windows  having 
walls  of  brick,  stone  or  terra  cotta 
start  above  the  first  story,  it  is  neces- 
sary to  support  them  in  some  way  by 
metal  work. 

If  the  bottom  of  the  bay  is  of  stone,  and  the  projection  is  not  more 
than  2  feet,  the  bay  may  be  supported  directly  from  the  wall  by  cor- 


Fig.  213. 


306  BUILDING  CONSTRUCTION. 

beling  out  the  stonework  as  shown  in  Fig.  213.  The  stoned  should 
be  the  full  size  of  the  bay  if  possible,  and  should  be  bolted  down  by 
means  of  long  rods  built  into  the  wall  and  secured  to  two  channel 
bars  (as  in  the  figure)  placed  on  top  of  the  stone  and  with  their 
ends  built  into  the  main  wall. 


IO  Beams 


Iron  Beari 
•  Plates 

' 


Fig.  214. 


If  the  bottom  of  the  bay  is  of  copper,  and  at  a  floor  level,  the  sim- 
plest and  strongest  method  of  supporting  the  bay  is  that  shown  in 
Fig.  214. 

Steel  I-beams  are  extended  across  the  wall  of  the  story  below  and 
framed  to  a  pair  of  channels,  bent  to  the  shape  of  the  bay.  The 
I-beams  should  be  carried  far 
enough  inside  of  the  walls  to  give 
them  a  sufficient  anchorage  to  off- 
set the  leverage  of  the  outer  end, 
and  should  be  secured  to  a  girder  or 
partition  running  parallel  with  the 
wall  or  to  another  steel  beam  at 
right  angles  with  them,  and  form- 
ing part  of  the  floor  construction. 

The  channel  bars  forming  the 
support  for  the  walls  of  the  bay 
should  also  be  built  into  the  wall 
on  each  side  and  anchored  by  iron 
rods  built  into  the  masonry  below. 

Fig.  215  shows  a  method  of  supporting  a  light  bay  by  cast  iron 
brackets  bolted  to  the  wall,  which  has  been  used  where  the  bottom 
of  the  bay  was  above  the  floor  line.  The  bottom  of  the  bay  in  this 


SKELETON  CONSTRUCTION.  307 

construction  may  be  either  of  copper  or  terra  cotta,  the  latter,  if  used, 
being  suspended  from  the  bracket  by  hook  anchors.  If  such  con- 
struction is  used  a  steel  channel  should  be  bolted  to  the  top  of  the 
wall  and  extended  well  into  the  side  walls,  to  prevent  the  brackets 
from  pulling  away  the  brickwork.  Examples  of  bay  supports  in  skel- 
eton construction  are  also  shown  in  Figs.  221  and  222. 

326.  Wall  Supports  in  Skeleton  Construction.— In  build- 
ings built  on  the  skeleton  plan,  now  so  generally  used  for  high  office 
buildings,  all  the  weight  of  the  walls,  including  the  masonry  surround- 
ing the  outer  columns,  is  supported  by  the  steel  skeleton,  at  least  above 
the  third  story.  The  outer  walls  of  the  lower  stories,  when  of  stone- 
work, are  sometimes  supported  directly  from  the  foundations,  as  was 
the  case  in  the  New  York  Life  Building,  Chicago.* 

When  the  walls  are  supported  by  the  steel  skeleton  they  are  gener- 
ally made  very  thin — about  12  inches,  and  sometimes  only  9  inches 
thick — and  in  the  more  recent  buildings  the  wall  is  supported  at  every 
story,  so  that  the  wall  in  any  story  could  be  removed  without  affecting 
the  wall  above  or  below. 

The  materials  generally  used  for  the  outer  walls  are  brick  and  terra 
cotta,  these  being  preferred  on  account  of  the  ease  with  which  they 
maybe  handled  and  the  facility  with  which  they  maybe  built  about 
and  between  the  beams  and  columns.  Brick  and  terra  cotta  also 
appear  to  be  about  the  only  suitable  materials  for  the  walls  of  a  fire- 
proof building. 

It  has  been  found  very  difficult  to  attach  stonework  to  the  metal 
frame,  and  this,  together  with  the  low  fire-resisting  qualities  of  most 
building  stones,  has  practically  prohibited  the  use  of  this  material 
except  in  the  lower  stories.  In  the  Reliance  Building,  Chicago,  thin 
slabs  of  highly  polished  granite  enclosed  in  ornamental  metal  frames 
were  used  for  casing  the  columns  in  the  first  story. 

The  general  plan  of  the  exterior  walls  in  this  class  of  buildings 
consists  of  vertical  piers,  from  3  to  4  feet  wide,  which  inclose  the 
exterior  columns  and  extend  from  the  bottom  to  the  top  of  the  build, 
ing.  The  space  between  these  piers  is  generally  nearly  filled  by- the 
windows,  either  flat  or  in  the  form  of  bays,  leaving  only  a  small  piece 
of  wall,  from  4  to  5  feet  high,  between  the  tops  and  bottoms  pf  the 
windows  to  be  supported  by  the  frame.  These  portions  of  wall 
between  the  piers  and  the  windows  are  called  spandrels-. 

The   mason  work  of   the   piers   is   generally  supported  by  angle 


1  Jenney  &  Mundie,  architects 


3°8 


B  UILDING  CONS  TR  UC  TION. 


brackets  attached  to  the  columns,  and  the  spandrels  are  supported 
by  steel  beams  or  girders  of  various  shapes,  called  spandrel  beams. 
The  spandrel  beams  extend  from  column  to  column,  and  are  riveted 
to  them. 

The  arrangement  of  the  metal  work  for  supporting  the  spandrel 
walls  will  depend  largely  upon  the  architectural  effect  sought  by  the 
designer  and  upon  the  materials  used,  so  that  the  details  vary  some- 
what in  every  building,  and  often  in  different  portions  of  the  same 
building.  No  general  rule  or  form  of  construction  can  therefore  be 
given  for  arranging  such  supports,  but  the  architect  must  use  such 
arrangements  as  seem  best  suited  to  the  design  of  the  building  he  has 
in  hand.  The  following  examples,  however,  will  show  how  the  walls 


LinesC-Con  center  of  Columns. 


Fig.  216. 


have  been  supported  in  several  buildings,  and  with  slight  variations 
•  one  or  another  of  these  methods  can  be  adapted  to  almost  any  build- 
ing. 

It  is  probably  hardly  necessary  to  say  that  the  melal  work  in  this 
class  of  buildings  should  be  very  carefully  designed  and  studied  to 
suit  the  conditions  of  the  building,  and  to  provide  ample  strength, 
as  well  as  arranged  so  that  it  may  be  fully  protected  from  heat.  Con- 
sideration must  also  be  given  to  the  effects  of  expansion  and  con- 
traction in  the  frame. 

327.  Spandrel  Supports. — The  simplest  case  of  spandrel  sup- 
ports is  where  the  wall  is  perfectly  plain  and  built  of  brick,  with 
terra  cotta  caps  and  sills.  In  such  cases  a  channel  and  angle  bar 
may  be  used  to  support  the  outer  face  of  the  wall  and  an  I-beam  the 


SKELETON  CONSTRUCTION. 


309 


backing,  as  shown  in  Fig.  216,  which  shows  sections  of  the  outer 
walls  of  the  Champlain  Building,  Chicago.* 

The  channel  and  I-beam  should  be  bolted  together  with  cast  sep- 
arators made  to  fit. 

For  a  plain  wall,  channels  and  angles  seem  to  be  the  best  shape  for 
the  outer  portion  of  the  spandrel  support,  as  they  are  of  an  economi- 
cal section,  and,  the  flat  face  of  the  channel  being  outward,  a  4-inch 
veneer  of  brick  can  be  set  in  front  of  it  without  clipping  the  'brick. 

The  face  of  the  chan- 
nel is  generally  set  5  or 
6  inches  from  the  face 
of  the  wall,  and  3x3 
angles  are  used  for 
supporting  the  outer 
' —  4  inches  of  wall.  The 
09  -  outer  edge  of  the  an- 
gle should  come  within 
z\  inches  of  the  face 
of  the  wall. 

Spandrel  supports 
very  similar  to  those 
shown  in  Fig.  216  have 
been  used  in  several 
Chicago  buildings. 

Z-bars  have  also 
been  used  in  several 
buildings  in  place  of 
the  channel  and  an- 
gle, but  are  not  gener- 
ally considered  quite 
as  satisfactory,  as  they 
do  not  give  the  same 
THKOUQH  >frr/c  ^  stren gth  for  the  weight 

Fig- 2I7>  of  metal  used. 

Fig.  217  shows  a  Z-bar  support  used  for  the  attic  wall  of  the  Wyan- 
dotte  Building,  Columbus,  Ohio.f 

Fig.  218,  from  the  New  York  Life  Building,  Chicago,  shows  the 
spandrel  supported  by  a  single  I-beam,  the  4-inch  facing  of  the  wall 
being  supported  by  the  terra  cotta  lintel  which  is  hung  from  the  beam. 


*  Holabird  &  Roche,  architects. 
t  D.  H.  Burnham  &  Co  ,  architects. 


3io 


BUILDING  CONSTRUCTION. 


In  the  Reliance  Building*  plate  girders  were  used  for  the  main 
spandrel  supports,  and  two  angles  riveted  together  to  make  a  T  were 
bracketed  from  the  outer  face  of  the  girder  to  support  the  wall,  the 
girder  being  on  the  centre  line  of  the  columns. 

Fig.  219  shows  the  method  used  for  supporting  the  granite  walls 
at  the  fourth  floor  level  of  the  Masonic  Temple,  Chicago.  It  should 
be  noticed  that  an  open  joint  is  left  opposite  the  supporting  angle  to 
allow  for  expansion  and  contraction  in  the  column. 

When  the  wall  is  faced  with  ornamental  terra  cotta  the  latter  can 
seldom  be  supported  directly  by  the  spandrel  beams,  and  a  system  of 

anchors  must  be    resorted  to,  to 
properly  tie  the  individual  blocks 
either  to  the  brick  backing  or  to 
the  metal  work.     These  anchors 
are  usually  made  of  |-inch  square 
or   round   iron    rods,  which  are 
hooked  into  the  ribs  provided  in 
the  terra  cotta  blocks,  and  then 
drawn  tight  to  the  brickwork  or 
metal      work      by 
PUNCH i  HOLES  6'ow  means  of  nuts  and 
cEirrcns  ro«  T  c.      screw      ends,      as 
shown  in  Fig.  221. 
Hook  bolts  are 
largely     used     for 
tying    terra    cotta 
blocks  to  the  metal 
work,  the  ends  be- 
ing bent  around  the 

bottom  of  the  beams,  channels  or  angles.     Several  examples  of  the 
use  of  hook  bolts  are  shown  in  Figs.  218,  220,  221  and  222. 

A  great  variety  of  methods  for  properly  securing  the  terra  cotta  are 
possible.  They  should  be  carefully  studied  and  the  general  scheme 
should  always  be  indicated  on  the  spandrel  sections,  in  the  manner 
shown  in  the  illustrations,  as  the  holes  in  the  structural  metal  work 
necessary  to  receive  the  anchors  should  be  shown  on  the  detail  draw- 
ings of  the  iron  and  steel  work,  so  that  the  punching  may  be  done 
at  the  shop.  The  inexperienced  architect  should  also  consult  with 


CNANICLEO 
BRICK 


Fig.  21 


'  D.  H.  Burnham  &  Co.,  architects. 


.VA'yT. 


'LETON  CONSTRUCTION.  3II 

the  manufacturers  of  the  terra  cotta  work  as  to  the  best  manner  of 
securing  the  blocks. 

The  anchorage  of  the  brick  and  terra  cotta  to  the  steel  frame  is  a 
matter  of  vital  importance,  as  very  serious  consequences  are  quite 

sure  to  follow  any  neglect  in 
this  matter.  "An  instance  is 
known  where  a  whole  section  of 
wall  facing  on  the  court  side  of 
a  high  building  fell  off  because 
the  workmen  omitted  the  an- 
chors." As  all  the  anchors  for 
every  block  cannot  be  exactly 
shown  on  the  drawings,  either 
the  architect  or  some  one  in  his 
employ  should  give  this  portion 
of  the  work  the  strictest  super- 
intendence. 

328.     Bay     Windows.— 

These  have  become  a  very 
prominent  feature  in  the  mod- 
ern office  building  and  hotel. 
In  skeleton  buildings  the  mason 
work  of  the  bays  is  made  as 
light  as  possible,  with  slight 
terra  cotta  mullions  and  angles, 
and  is  supported  in  each  story 
by  brackets  built  out  from  the 
sprndrel  beams  or  girders,  as 
shown  in  Figs.  221  and  222, 
which  are  sections  from  the 
Wyandotte  Building. 

As    the    leverage    on     these 
brackets   is   considerable,   they 

should  be  securely  riveted  to  the  spandrel  beam,  and  the  latter  well 
tied  or  framed  to  the  floor  construction  to  keep  it  from  twisting. 

Where  mullions  occur  between  windows,  and  at  the  angles  of  the 
bays,  cast  iron  or  steel  angle  or  T-bars  are  bolted  or  riveted  to  the 
metal  work  above  and  below,  to  stay  the  frames  and  terra  cotta  mul- 
lions and  angles,  in  the  manner  shown  in  Fig.  223. 

The  importance  of  thoroughly  fireproofing  the  exterior  columns 


3i2  BUILDING  CONSTRUCTION. 

has  already  been  considered  in  Chapter  IX.  Fig.  223,  however,  is 
given  as  an  example  of  the  pier  construction  in  Chicago  buildings 

Further  illustrations  of  the  manner  of  supporting  the  mason  work 
in  this  class  of  buildings  may  be  found  in  Architectural  Engineering, 
by  Joseph  K.  Freitag,  C.  E.,  and  several  numbers  of  the  Engineering 
Record  and  the  Brickbuilder. 

329.  Miscellaneous  Ironwork. — The  following  details  of  iron- 
work used  in  connection  with  brickwork  and  stonework  should  per- 


Fig.  220.— Section  New  York  Life  Building. 

haps  be  mentioned  here,  as  they  have  to  be  considered  when  design- 
ing the  mason  work. 

Bearing  Plates. — Wherever  iron  or  wooden  posts,  columns  or  gird- 
ers rest  on  brickwork,  a  cast  iron  or  stone  bearing  plate  should  be 
used  to  distribute  the  concentrated  weight  over  a  safe  area  of  the 
mason  work.  Several  failures  in  buildings  have  resulted  from  care- 
lessness in  this  particular.  Rules  for  proportioning  the  size  of  bear- 
ing plates  are  given  in  the  Architects'  and  Builders'  Pocket  Book. 

Cast  Iron  Skewbacks  for  Brick  Arches. — Wherever  segmental 
arches  are  used  over  doors  or  windows,  without  ample  abutments, 


SKELETON  CONSTRUCTION. 


cast  iron  skewbacks,  connected  by  iron  rods  of  proper  size,  should 
be  used  to  take  up  the  thrust  of  the  arch,  as  shown  in  Fig.  224. 

Shutter  Eyes. — All  fireproof  doors  and  shutters  in  brick  or  stone 
walls  should  have  hinges  made  of  2x^-inch  flat  iron  bars,  welded 
around  a  ^-inch  diameter  pin  working  in  a  cast  iron  shutter  eye 
built  into  the  wall.  For  brick  walls  the  shape  shown  at  a,  Fig.  225, 


•"1 


u 


— T 


i     1 


is  about  the  best  for  the  eyes,  although  for  very  heavy  doors  or  shut- 
ters the  strength  of  the  face  should  be  increased  by  having  another 
web.  For  stone  walls  the  shape  shown  at  b  should  be  used.  The 
thickness  of  the  metal  is  generally  made  }/±  of  an  inch. 

Door  Guards  and  Bumpers.— -It  is  a  good  idea  to  protect  the  brick 
jambs  of  the  carriage  doors  in  stables  by  bumpers,  which  are  rounded 
projections  on  the  corners  extending  12  to  1 8  inches  above  the  ground 


3*4 


BUILDING  CONSTRUCTION. 


and  about  8  inches  beyond  the  wall  and  jamb,  so  that  if  the  carnage 
wheel  strikes  the  bumper  the  hub  will  not  scratch  the  brick  jamb. 
Such  bumpers  may  be  made  either  of  some  hard  stone  or  of  iron. 


I. -11      '  _.^T= 


Fig.  222. — Section  Through  Top  of  Bays. 


%'"  ~  * 


Fig.  223  —Plan  of  Piers  and  Mullions  in  Alley  and  Light  Court, 
New  York  Life  Building,  Chicago. 

The  jambs  of  the  exterior  doors  to  freight  elevators  and  of  the  deliv- 
ery and  receiving  doorways  in  mercantile  buildings  should  also  be 
protected  for  a  height  of  4  or  5  feet  above  the  sill  by  iron  guards,  to 


SKELETON  CONSTRUCTION. 


prevent  the  brickwork  being  broken  by  boxes,  trucks,  etc.  Such 
guards  are  generally  made  of  cast  iron  about  \  inch  thick,  as  castings 
can  more  easily  be  fastened  to  the  wall  than  plate  iron.  The 


Fig.  224. 


Fig.  225. 


castings,  or  plates,  should  be  made  with  lugs  on  the  inside  pierced 
with  holes  for  clamping  them  securely  to  the  brickwork  as  the  wall  is 
built.  Fig.  226  shows  a  section  of  one  of  the  alley  piers  of  the  New 


IRON  WHEEL  GUARD 


Fig  226. 


York  Life  Building,  Chicago,  and  the  manner  in  which  the  iron 
guards  are  attached  to  the  brickwork.  A  similar  arrangement  can  be 
•adapted  to  any  door  jamb.  In  Chicago  it  is  quite  common  to  protect 


BUILDING  CONSTRUCTION. 


Fig.  227. 


the  bottoms  of  the  piers  on  the  alleys  in  this  way  to  prevent  injury  to- 

the  walls  from  passing  teams. 

330.  Chimney  Caps. — For  tall  chimneys  a  cast  iron  cap  is  gen- 
erally considered  the  most  durable  finish  for  the  top.     The  usual 

shape  of  such  caps  is 
that  shown  in  Fig.  227. 
Such  a  cap  completely 
protects  the  mortar 
joints  from  the  weather 
and  prevents  the  bricks 
in  the  upper  courses 
from  becoming  loose. 
If  the  chimney  is  cor- 
beled out  as  shown  the 

cap  also  acts  as  a  drip  to  protect  the  sides  of  the  chimney,  at  least 

near  the  top.     The  inner  lip  of  the  cap  should  extend  down  into  the 

chimney  from  8  to  12  inches.     If  the  cap  is  not  larger  than  4  feet 

square  it  need  be  but  \  of  an  inch  thick  ;  if  larger  than  this  the 

thickness  should  be  increased  to  -f  inch. 

If  the  cap  is  3  feet  square  or  greater,  for  convenience  in  handling 

and  casting  it  should  be"made  in  two  or 

four  sections,  which  should  be  bolted      Z 

together,  flanges  being  cast  on  the  under      r 

side  for  this  purpose. 

Chimney   Ladders. — It    is    sometimes      ^ 

desirable  to  have  a  ladder  built  inside      ~ 

of  large  brick  flues,  or  shafts,  and  on  the      ffi 

outside  of  tall  chimneys  to  serve  as  a      ~ 

ready  means  of  reaching  the  top.     Such 

ladders  are  usually  made  of  |-inch  round 

iron  bars,  bent  to  the  shape  shown  in     - 

Fig.  228  and  placed  in  the  wall  of  the 

chimney,  or  flue,  when  built.     For  easy 

climbing  the  rungs  should  be  placed  12 

inches  apart  between  centres,  and  should 

be  about  18  inches  wide  and  project  6 

inches  from  the  wall. 

Coal  Hole  Covers  and  Frames. — When  coal  vaults  are  placed  under 

the  sidewalk  the  architect  should  specify  iron  frames  and  covers  for 

the  holes  made  for  putting  in  the  coal.     If  the  vault  is  covered  with 

granite  flagging  a  rebate  may  be  cut  in  the  stone  to  receive  the  cover, 


FRONT 


SKELETON  CONSTRUCTION.  317 

and  no  frame  is  necessary.  In  all  other  stones,  and  in  cement  walks, 
the  hole  should  be  protected  by  a  cast  iron  frame  at  least  4  inches 
deep.  The  frame  is  generally  cast  with  a  projecting  ring  about  2 
inches  wide  and  \  inch  thick,  which  should  set  in  a  rebate  cut  in  the 
stone  and  filled  with  soft  Portland  cement.  The  frame  is  also  made 
with  a  |^-inch  rebate  for  the  iron  cover.  The  cover  is  made  of  cast 
iron  about  \  inch  thick  and  should  have  a  roughened  surface 
on  top.  The  covers  are  sometimes  made  with  holes,  into  which  glass 
bull's  eyes  are  cemented  to  admit  light  to  the  vault.  Both  solid  and  < 
glazed  covers  are  generally  carried  in  stock  by  the  larger  iron  foun- 
dries, and  in  sizes  from  1 6  to  24  inches  in  diameter. 


CHAPTER  XI. 
LATHING  AND  PLASTERING. 


331.  Probably  99  per  cent,  of  modern  buildings,  in  this  country 
at  least,  have  plastered  walls,  ceilings  and  partitions.    It  is  only  lately, 
however,  that  much  attention  has  been  given  to  this  branch  of  build- 
ing operations,  and  there  is  probably  no  doubt  but  that  much  of  the 
plastering  done  at  the  present  day  is  inferior  to  that  done  fifty  or  one 
hundred  years  ago. 

The  introduction  of  fireproof  construction  and  the  desirability  of 
completing  large  and  costly  business  buildings  in  the  shortest  pos- 
sible time  has  shown  the  necessity  for  improvements  in  the  materials 
used  both  for  the  lathing  and  the  plastering,  and  several  new  mate- 
rials have  been  introduced  to  meet  the  demand. 

Even  in  dwellings  it  is  important  that  the  finish  of  the  walls  and 
ceilings  shall  be  as  nearly  perfect  as  possible,  as  large  sums  of  money 
are  not  infrequently  spent  on  their  decoration,  and  it  is  therefore 
essential  that  the  ground  work  shall  be  so  durable  that  the  decora- 
tions will  not  be  ruined  by  broken  walls  or  falling  ceilings.  The 
quality  of  the  workmanship  is  also  of  much  importance,  as  nothing 
mars  the  appearance  of  a  room  more  than  crooked  walls  and  angles, 
and  dents,  cracks  and  patches  in  the  plastering. 

To  secure  a  good  job  of  lathing  and  plastering  it  is  essential  that 
only  the  best  materials  be  specified  and  used,  and  that  the  mortar  be 
properly  prepared  and  applied.  These  can  only  be  insured  by  being 
careful  to  specify  exactly  how  the  work  shall  be  done  and  the  mate- 
rials that  shall  be  used,  and  supplementing  the  specifications  by  effi- 
cient supervision.  In  order  to  furnish  such  specifications  and  super- 
intendence, it  is  obviously  necessary  that  the  architect  shall  be  thor- 
oughly familiar  with  the  materials  used  and  the  way  in  which  they 
should  be  applied. 

LATHING. 

332.  Brick  walls  and  hollow  tile  ceilings  and  partititions  do  not 
require  lathing,  as  the  plastering  may  be  applied  to  them  directly,  the 
brick  and  tiles  having  an  affinity  for  the  mortar  which    holds  it 


LATHING  AND  PLASTERING. 


securely  in  place.     All  other  constructions  require  some  form  of 
lathing  to  serve  as  a  ground  to  receive  and  hold  the  plaster. 

Wooden  Laths.—  Practically  all  dwellings  of  moderate  cost, 
and  a  large  proportion  of  other  buildings,  are  still  lathed  with  wooden 
laths,  and  if  of  good  quality  they  give  very  satisfactory  results  where 
no  fireproof  quality  is  expected.  It  is  generally  admitted  that  the 
best  wood  for  laths  is  white  pine,  although  nearly  as  many  are  made 
of  spruce,  which  answers  very  well.  Hard  pine  is  not  a  good  mate- 
rial for  laths,  as  it  contains  too  much  pitch. 

Wooden  laths  should  be  well  seasoned  and  free  from  sap,  bark  and 
dead  knots.  Small  sound  knots  are  not  particularly  objectionable. 
Bark  is  often  found  on  the  edges  of  laths,  and  is  probably  the  great- 

est defect  that  they  are  subject 
to,  as  it  is  quite  sure  to  stain 
through  the  plaster. 

The     usual     dimensions    of 
wooden  laths  are  £xi£   inches 
in  section  and  4  feet  long  ;  the 
width  and  thickness  vary  some- 
what in  different  mills,  but  the 
length  is  always  the  same.    The 
studding  or  furring  strips  should 
therefore  be  spaced  either    12 
or   1  6  inches  apart  from  cen- 
tres ;  12-inch  spacing  gives  five 
nailings  to  the  lath,  and  i6-inch 
spacing  four  nailings. 
The  former  obviously  makes  the  stronger  and  better  wall.     It  is 
particularly  desirable  that  laths  on  ceilings  have  five  nailings,  as  there 
is  more  strain  on  them  than  on  those  on  the  walls. 

Sheathing  Lath.  —  Some  years  ago  a  combined  sheathing  and  lath, 
known  as  the  Byrkit-Hall  Sheathing  Lath,  was  placed  on  the  market. 
This  lath  is  made  of  |-inch  boards,  8  inches  wide  and  of  regular 
lengths,  grooved  as  shown  in  Fig.  229.  To  what  extent  it  has  been 
used  the  author  is  not  informed,  but  it  would  appear  to  be  an  excel- 
lent material  for  sheathing  the  outside  walls  of  wooden  buildings  that 
are  to  be  back  plastered.  Such  sheathing  plastered  on  the  inside 
will  make  a  very  warm  'house,  and  effect  much  saving  in  the  cost  of 
heating.  It  is  also  claimed  that  this  lath  is  superior  to  the  wooden 
lath  for  inside  work,  although  one  would  naturally  suppose  that  the 
shrinkage  of  the  wood  would  cause  the  plastering  to  crack.  It  cer- 


Fig.  229.— Byrkit-Hall  Sheathing  Lath. 


320 


BUILDING  CONSTRUCTION. 


tainly  makes  a  saving  in  the  amount  of  mortar  used,  and  also  has  the 
advantage  that  a  nail  can  be  driven  into  it  anywhere  without  spoiling 
or  loosening  the  plastering.  A  special  lath  is  made  for  hard  plasters, 
adamant,  etc. 

333.  Metal  Laths. —  Wire  Cloth. — About  eighteen  years  ago, 
when  the  interest  in  fireproof  construction  became  more  general, 
wire  netting  came  into  use  as  a  substitute  for  the  wood  lath.  It  was 
found  that  the  strands  of  the  netting  became  completely  imbedded  in 
the  plaster  and  held  it  so  securely  that  it  could  not  become  detached 
by  any  ordinary  accidents.  The  plaster  also  protects  the  wire  from 
the  heat,  and  the  body  of  the  metal  is  so  small  that  there  is  no 
appreciable  expansion  of  the  metal  when  subjected  to  fire. 

The  author  believes  that  heavy  wire  cloth  tightly  stretched  over 
metal  furrings  forms  the  most  fireproof  lath  now  on  the  market,  and 
he  has  personally  seen  it  demonstrated  by  severe  experimental  tests, 
and  by  actual  fires  in  buildings,  that  plaster  on  wire  cloth,  and  par- 
ticularly hard  plasters,  will  protect  the  woodwork  from  a  severe  fire 
so  long  as  the  plaster  remains  intact,  provided  there  are  no  cracks  or 
loopholes  at  the  corners  and  around  columns  where  the  fire  can  get 
through. 

The  objection  has  been  found  to  the  ordinary  wire  lath  that  it  is  diffi- 
cult to  stretch  it  so  tight  that  it  will  not  yield  to  the  pressure  exerted 
in  applying  the  several  coats.  Another  objection  that  is  made  to  the 
wire  lath,  and  also  to  the  expanded  lath  (Fig.  231),  is  that  they  take 
a  great  deal  of  plaster.  From  tlje  standpoint  of  first  cost  this  is 
undoubtedly  a  valid  objection,  but  from  a  fireproof  standpoint  the 
great  amount  of  mortar  used  is  its  principal  value.  It  should  be 
remembered  that  the  mortar  is  the  fireproof  part  of  the  wall  or  ceil- 
ing, and  not  the  metal.  No  metallic  lath,  the  author  believes,  should 
be  considered  as  fireproof  which  does  not,  in  use,  become  imbedded  in 
the  mortart  for  if  the  thin  coating  of  plaster  peels  off  the  metal  lath 
will  resist  the  fire  no  better  than  the  wood  lath,  and  will  be  more  in 
the  way  of  the  fireman. 

Wire  lathing  is  now  made  in  great  variety  to  meet  the  requirements 
of  the  different  plastering  compositions  and  the  varying  conditions  of 
construction. 

Plain  lathing  is  plain*  wire  cloth,  usually  2^x2^  meshes  to  the  inch, 
made  from  No.  17  to  No.  20  wire.  No.  20  is  more  generally  used 
than  any  other  size. 


*The  word  plain  is  here  used  to  designate  ordinary  wire  cloth,  without  corrugations  or  stiff- 
ening bars.  As  used  by  the  trade-  the  word  "  plain  "  means  lathing  that  is  not  painted  or 
galvanized. 


LATHING  AND  PLASTERING.  321 

The  lathing  is  also  sold  plain,  painted  and  galvanized.  Painted  or 
galvanized  lathing  should  be  used  in  connection  with  special  hard 
plaster  compounds.  Painted  lathing  costs  about  one  cent  per  square 
yard  more  than  "bright"  lathing. 

Galvanizing  the  wire  cloth  after  it  is  woven  adds  very  much  to  its 
stiffness,  as  the  zinc  solders  the  wires  together  where  they  cross. 
Galvanized  lathing  is  also  less  liable  to  corrosion  before  the  plaster- 
ing is  applied  than  the  plain  lathing. 

The  usual  widths  of  wire  lathing  are  32  and  36  inches,  although 
the  Roebling  lath  may  be  obtained  of  any  width  up  to  8  feet. 

All  wire  lathing  should  be  stretched  tight  when  applied,  so  as  to 
insure  a  firm  surface  for  plastering.  For  this  purpose  stretchers  are- 
supplied  by  the  manufacturers. 

Furring  for  Wire  Lath. — In  order  to  properly  protect  wooden  con- 
struction, such  as  beams,  posts,  studding  or  plank,  from  fire,  by  wire 
lath  and  plaster,  it  is  essential  that  the  lath  be  kept  at  least  f  inch  away 
from  the  woodwork  by  iron  furring  of  some  form,  and  a  i-inch  space  is 
much  better.  This  setting  off  of  the  lath  from  the  wood  is  generally 
done  either  by  means  of  bars  woven  into  or  attached  to  the  lathing, 
or  by  means  of  iron  furring  put  up  before  the  lathing.  Probably  the 
most  common  method  of  furring  with  iron  for  wire  lath  has  been  by 
means  of  band  iron,  either  straight  or  corrugated,  \  inch  or  f  inch 
wide,  set  on  edge  and  secured  to  the  under  side  of  the  joist  or  plank 
by  narrow  staples,  driven  so  as  to  keep  the  iron  in  a  vertical  position. 

On  floor  beams  and  studding,  unless  heavy  iron  is  used,  it  is  nec- 
essary to  run  the  furring  lengthways  of  the  beams  and  studding,  and, 
as  the  latter  are  seldom  less  than  12  inches  on  centres,  this  does  not 
give  close  enough  bearings  to  secure  a  stiff  surface  for  the  plastering. 

Under  plank  (mill)  floors  the  band  iron  should  be  spaced  every  8 
inches,  and,  if  corrugated  iron  is  used,  a  very  satisfactory  surface  is 
obtained.  After  the  furring  is  fixed  in  place  the  cloth  is  then 
stretched  over  it  and  secured  by  staples  nailed  over  the  wire  and  the 
band  iron. 

Hammond's  Metal  Furring*— A  much  better  system  of  furring,  and, 
so  far  as  the  author  is  informed,  the  most  perfect  of  ^11  systems  of  sepa- 
rate furring  over  woodwork,  is  that  known  as  the  "Hammond"  furring, 
and  shown  by  Fig.  230.  It  consists  of  a  combination  of  sheet  metal 
bearings  and  steel  rods.  The  rods  form  the  furring  for  keeping  the 
wire  cloth  away  from  the  timber,  and  the  bearings  form  the  offset  for 
the  rods,  both  being  secured  to  the  joist,  studding  or  plank  by  means 
of  staples,  as  shown  in  the  figure.  The  rods,  being  only  about  \  inch 

*  Controlled  by  the  Gilbert  &  Bennett  Manufacturing  Co. 


322  BUILDING  CONSTRUCTION. 

in  diameter,  become  completely  imbedded  in  the  plaster  when  it  is 
applied,  and  as  the  plaster  hardens  it  unites  the  rod  and  cloth  so  as 
to  make  a  much  more  rigid  surface  than  is  possible  where  band  iron 
furring  is  used.  The  rods  also  may,  and  in  fact  should  be,  run  across 
the  beams  or  studding,  and  may  therefore  be  spaced  as  close  together 
as  desired.  It  is  recommended  that  the  spacing  of  the  rods  be  made 
1\  inches  where  the  joist  are  12  inches  on  centres  and  6  inches  when 
the  joist  are  16  inches  on  centres  (being  5  and  6  bars  to  each  strip  of 
lathing).  The  bearings  are  \  inch  and  i  inch  deep,  the  latter  being 
recommended,  as  they  give  a  greater  air  space  between  the  plaster  and 
timber,  which  is  especially  desirable  in  lathing  around  solid  timbers 

or  under  planking.  The 
rods  come  in  lengths  of 
about  10  feet. 

This  system  of  furring  is 
applicable  to  wooden  posts,, 
partitions  and  any  form  of 
wood  construction  ;  it  is 
readily  put  up,  and  is  but 
little  more  expensive  than 
band  iron.  After  the  fur- 
ring is  in  place  the  wire 
cloth  (which  should  be 
No.  20  gauge,  and  painted 
or  galvanized  if  hard  plas- 
ters are  to  be  used)  is 
Fig-  23°-  stretched  over  it,  prefer- 

ably in  the  same  direction  as  the  rods,  and  secured  by  staples  driven 
over  the  wire  and  one  side  of  the  bearing,  as  shown  in  the  figure. 

Corrugated  Wire  Lathing. — A  lathing  made  of  flat  sheets  of  double 
twist  warp  lath,  with  corrugations  f  of  an  inch  deep  running  length- 
wise of  the  sheet  at  intervals  of  6  inches,  has  been  used  to  some 
extent.  The  sheets  are  made  8x3  feet  in  size  and  applied  directly  to 
the  under  side  of  the  floor  timbers,  to  partitions  or  to  brick  walls,  and 
fastened  with  staples.  The  corrugations  afford  space  for  the  mortar 
to  clinch  behind  the  lath,  and  thus  do  away  with  the  necessity  for 
furring  strips ;  they  also  strengthen  the  lathing. 

Stiffened  Wire  Lathing. — In  order  to  avoid  the  labor  and  expense 
of  furring  with  metal,  wire  lathing  having  the  furring  strips  attached 
to  the  fabric  was  introduced  some  years  ago,  and  has  been  very 
extensively  used,  and  the  author  would  recommend  that  whenever 


LATHING  AND  PLASTERING.  323 

wire  lathing  is  used  over  wood  construction  that  either  one  of  the 
stiffened  wire  laths,  or  ordinary  wire  cloth  with  the  Hammond  f  urring, 
be  specified. 

Two  varieties  of  stiffened  wire  lathing  are  now  on  the  market. 
Each  has  been  extensively  used,  with  satisfactory  results. 

The  Clinton  stiffened  lath  has  corrugated  steel  furring  strips 
attached  every  8  inches  crosswise  of  the  fabric  by  means  of  metal 
clips.  These  strips  constitute  the  furring,  and  the  lath  is  applied 
directly  to  the  under  side  of  the  floor  joist,  or  to  planking^  furring, 
brick  walls,  etc.  This  lath  is  made  in  3  2 -inch  and  36-inch  widths 
and  comes  in  loo-yard  rolls. 

The  Roebling  stiffened  lathing,  made  by  the  New  Jersey  Wire 
Cloth  Co.,  is  made  of  plain  wire  cloth,  in  which,  at  intervals  of  i\ 
inches,  stiffening  ribs  are  woven.  These 
ribs  have  a  V-shaped  section  and  are 
made  of  No.  24  sheet  iron,  and  vary 
from  |  to  \\  inches  in  depth.  The 
f-inch  rib  is  the  standard  size  for  lathing 
on  woodwork.  This  lathing  requires  no 
furring,  and  is  applied  directly  to  wood- 
work or  walls  with  steel  nails  driven 
through  the  bojttom  of  the  V,  as  shown, 
in  Fig.  230  A. 

23oA  The    No.    20   V-rib  stiffened  lathing 

affords  a  satisfactory  surface  for  plas- 
tering, when  attached  to  studs  or  beams  spaced  16  inches  apart. 
The  lathing  should  be  applied  so  that  the  widths  will  join  on  a  beam 
or  stud. 

The  i^-inch  V-rib  lathing  is  used  for  furring  exterior  walls.  It 
provides  an  air  space  between  the  wall  and  plaster. 

For  iron  construction  a  J-inch  solid  steel  rod  is  substituted  for  the 
V-rib,  and  the  lathing  is  attached  to  light  iron  furring  with  lacing  wire. 
The  Roebling  lath  is  made  with  2^x2^,  3x3  and  3x5  mesh,  the 
latter  being  known  as  "close-warp."  The  2^x2^  mesh  should  be 
used  for  ordinary  lime  and  hair  mortar,  and  the  3x3  or  3x5  mesh 
for  hard  plasters  and  thin  partitions.  This  lathing  is  also  sold  bright,, 
painted  and  galvanized. 

The  No.  20  painted  wire  has  been  extensively  used,  and  much  of 
it  has  been  in  service  for  from  6  to  8  years  and  is  now  apparently  as 
good  and  strong  as  ever,  so  that  there  appears  to  be  no  necessity  in 
ordinary  work  of  using  heavier  wire  or  galvanized  netting. 


324 


BUILDING  CONSTRUCTION. 


The  galvanized  wire  is  stiffer  than  the  painted,  and  would  possibly 
wear  longer,  but  it  is  doubtful  if  the  advantages  ai£  at  all  propor- 
tionate with  the  cost. 

334.  Expanded  Metal  Lath. — This  lath  (Fig.  231),  now  prob- 
ably well  known  to  architects,  is  made  from  strips  of  thin,  soft  and 
tough  steel  by  a  mechanical  process  which  pushes  out  or  expands 
the  metal  into  oblong  meshes,  and  at  the  same  time  reverses  the 
direction  of  the  edge,  so  that  the  flat  surface  of  the  cut  strand  is  at 
right  angles  with  the  general  surface  of  the  sheet. 

Two  sizes  of  meshes  are  made,  T^XI^  inches  and  |xi£  inches,  the 
former  being  best  adapted  for  the  hard  mortars  and  the  latter  for 
lime  mortar.  Both  kinds  are  made  in  sheets  8  feet  long  and  from  14 
to  20  inches  in  width,  18  inches  being  the  standard  width. 

This  lath  being  flat  and  of 
considerable  stiffness  does  not 
require  to  be  stretched,  and  can 
be  fastened  directly  to  the  under 
side  pf  floor  joist  or  to  wood 
studding.  If  used  on  plank  it 
should  be  fastened  over  metal 
furring  strips.  When  applied 
to  studding  the  lath  should  be 
placed  so  that  the  long  way  of 
the  mesh  will  be  at  right  angles 
to  the  studding,  as  shown  in 
Fig.  231,  as  this  insures  the 
greatest  rigidity.  The  studding 
or  furring  strips  should  be  spaced  12  inches  on  centres  and  the  lath- 
ing secured  with  staples  i  inch  long,  driven  about  5  inches  apart  on 
the  stud  or  joist.  The  lath,  when  applied,  is  a  scant  \  inch  thick, 
and  to  obtain  a  good  wall  £-inch  grounds  should  be  used. 

There  are  several  companies  manufacturing  this  lathing  under  ter- 
ritorial rights,  and  it  has  been  extensively  used  with  very  satisfactory 
results.  The  author  believes  it  to  be  the  most  fireproof  lath  made 
from  sheet  metal. 

335.  Perforated  Sheet  Metal   Laths.— There  are  oorne  six 
or  more  styles  of  metal  lath  made  from  sheet  iron  or  steel  by  perforat- 
ing the  sheets  so  as  to  give  a  clinch  to  the  mortar.     The  sheets  are 
generally  corrugated  or  ribbed,  also,  in  order  to  stiffen  them  and  keep 
them  away  from  the  wood.     There  is  not  a  great  difference  between 


Fig.  231 


LATHING  AND  PLASTERING.  325 

these  laths,  although  some  styles  may  possess  certain  advantages  over 
the  others.  • 

In  general,  the  author  would  prefer  those  styles  which  have  the 
greatest  amount  of  perforations,  or  which  approach  the  nearest  to  the 
expanded  lath.  All  of  these  laths  come  in  flat  sheets  about  8  feet 
long  and  15  to  24  inches  in  width,  and  are  readily  applied  to  wood- 
work by  means  of  barbed  wire  nails.  The  nails  should  be  driven 
every  3  inches  in  each  bearing,  commencing  at  the  centre  of  the  sheet 
and  working  toward  the  ends.  These  lath  work  very  nicely  in  form- 
ing round  corners  and  coves,  and  are  generally  preferred  to  the  wire 
lath  by  plasterers,  as  they  are  easier  to  put  on.  They  are  certainly 
much  superior  to  wood  laths.  Metal  lath  should  never  be  cut  at  the 
angles  of  a  room,  but  bent  to  the  shape  of  the  angle  and  continued 

to  the  next  stud  beyond.  This 
strengthens  the  wall  and  pre- 
vents cracks  at  the  angles. 

Of  the  various  forms  of 
sheet  metal  lath  in  common  use, 
the  Bostwick  lath  (Fig.  231  A) 
is  perhaps  the  best  known 
and  most  extensively  used. 
It  is  made  of  sheet  steel,  with 

Fi         A  ribs  every  f  of  an  inch  in  the 

width  of  the  sheet,  and  loops, 

fxif  inches,  punched  out  between  the  ribs ;  the  lath  should  be 
applied  with  the  loop  side  out.  This  lath  can  be  put  on  as  fast  as 
the  wood  lath,  and  is  especially  well  adapted  to  round  corners  and 
coves. 

Picture  mouldings  should  always  be  placed  around  all  rooms  lathed 
with  metal  lath,  although  screws  can  be  quite  readily  secured  in  the 
lath  by  first  making  a  small  hole  with  a  punch  or  drill. 

When  using  common  lime  mortar  on  metal  lath  the  first  coat  should 
be  gauged  with  plaster  of  Paris.  Either  painted,  galvanized  or 
japanned  lath  should  always  be  used  for  hard  plasters  made  by  a 
chemical  process,  such  as  King's  Windsor  and  adamant. 

Aside  from  their  fireproof  qualities,  wire  or  metal  laths  possess  the 
advantages  that  plastering  applied  to  them  will  not  crack  from 
shrinkage  in  the  woodwork,  nor  can  the  plaster  fall  off.  If  the  lath- 
ing is  set  away  from  the  wood  studding,  the  location  of  the  timbers 
will  not  be  shown  by  the  plaster,  as  is  invariably  the  case  after  a  few 
years  when  wood  laths  are  used.  Metal  laths  are  also  proof  against 


326  BUILDING  CONSTRUCTION. 

rats  and  mice,  which  makes  them  especially  desirable  in  certain  kinds 
of  store  buildings.  Nearly  all  these  advantages  are  lost  when  unstiff- 
ened  wire  cloth  is  stretched  over  wood  furrings. 

336.  Plaster    Boards. — Thin  boards  made  of  plaster,  and  reeds 
or  fibre,  have  also  been  quite  extensively  used,  not  exactly  as  a  lath, 
but  as  a  ground  for  the  second  and  third  coats  of  plaster.     They  are 
made  in  slabs  about  f  inch  thick,  16  inches  wide  and  4  feet  long. 
The  Mackite  boards  are  made  f  inch   and  i  inch  thick  for  ordi- 
nary work.     The  under  surface  of  the  boards  should  be  grooved  or 
left  rough  to  receive  the  plastering. 

The  materials  of  which  the  boards  are  made  consist  chiefly  of  plas- 
ter of  Paris  and  some  sort  of  fibre.  The  Mackite  boards  also  have 
hollow  reeds  imbedded  in  them.  The  boards  can  be  sawed  into  any 
size  or  shape  and  nailed  directly  to  the  under  side  of  the  joist,  or  to 
studding  or  furring.  They  are  rapidly  put  on  and  require  no  scratch 
coat,  and  with  some  styles  of  boards  a  white  or  finished  coat  is  all 
that  is  necessary. 

Actual  fire  tests  appear  to  show  that  fire  does  not  harm  the  plaster 
board  more  than  the  terra  cotta  tile,  and  on  account  of  their  light- 
ness, and  the  ease  with  which  they  can  be  cut,  they  are  sometimes  pre- 
ferred to  tile  or  terra  cotta  for  suspended  ceilings  under  iron  beams. 

Owing  to  the  saving  of  plaster,  the  low  cost  of  the  boards  and  the 
ease  with  which  they  are  put  up,  plaster  boards  probably  offer  the 
cheapest  fireproof  ceiling  yet  devised. 

In  using  plaster  boards,  or  any  of  the  patented  laths,  the  architect 
or  builder  should  follow  the  directions  of  the  manufacturers  as  to  the 
manner  of  putting  up,  etc.,  as  there  are  often  important  precautions 
which  might  otherwise  be  overlooked. 

337.  Where   Metal  Lathing  Should   be   Used.— It  is  of 
course  desirable  that  metal  lathing  or  plaster  boards  should  be  used 
wherever  any  lathing  is  required,  but  the  increased  expense  gener- 
ally prevents  their  use  in  the  majority  of  buildings. 

There*  are,  however,  many  places  where  it  is  particularly  desirable, 
especially  in  buildings  having  ordinary  wood  floors  and  partitions. 
Such  places  are  the  under  side  of  stairs  in  public  buildings,  the  ceil- 
ings in  audience  and  assembly  rooms,  under  side  of  galleries,  ceilings 
of  boiler  and  furnace  rooms,  etc. 

Metal  lathing  should  also  be  used  on  wood  partitions,  on  both 
sides  of  hot  air  pipes.  Where  there  are  slots  in  brick  walls  for 
plumbing,  hot  air  or  steam  pipes,  they  should  be  covered  with  metal 
lath,  unless  the  walls  are  furred  or  the  recesses  cased  with  boards. 


LATHING  AND  PLASTERING.  327 

Metal  lath  should  also  be  used  at  the  junction  of  wood  partitions 
and  brick  walls,  when  the  walls  are  not  furred,  and  particularly  when 
the  partition  is  parallel  and  flush  with  the  wall. 

By  using  a  strip  of  wire  cloth  or  expanded  metal,  lapped  12  inches 
on  the  wall  and  partition,  a  crack  at  the  juncture  of  the  two  will  be 
avoided,  and  at  only  a  very  slight  additional  expense. 

It  very  often  happens  in  outside  brick  walls  that  the  arched  wooden 
lintels  over  the  windows  come  partly  above  the  casing,  and  if  the  wall 
is  plastered  directly  onto  the  brick  the  plastering  generally  cracks 
over,  or  will  not  stick  to  the  lintel.  This  can  be  avoided  by  cover- 
ing the  lintel  with  a  strip  of  metal  lath,  lapped  6  or  more  inches  on 
the  brickwork. 

In  general,  wherever  solid  timber  has  to  be  plastered,  without 
room  for  furring  and  lathing,  it  should  be  covered  with  metal  lath, 
which  should  also  be  lapped  well  on  to  the  adjoining  partition  or  wall. 

PLASTERING. 

338.  Interior  Work.— The  very  general  practice  of  plastering 
walls  and  ceilings  dates  back  not  much  more  than  a  century  ago. 
Previous  to  that  time  the  walls  and  ceilings  were  either  wainscoted, 
boarded,  or  covered  with  canvas  or  tapestries,  or  else  left  rough. 

On  account  of  its  cheapness,  its  fireproof  and  deafening  qualities, 
and  its  adaptability  to  decorative  treatment,  some  kind  of  plastering 
will  probably  always  be  used  for  finishing  the  interior  walls  and  ceil- 
ings of  buildings. 

In  describing  plastering  operations,  it  will  be  more  convenient  to 
divide  the  subject  under  the  heads  of  Lime  Plaster,  Hard  or  Cement 
Plaster,  Stucco  Work  and  Exterior  Plastering. 

Lime  Plaster. — Materials.— Lime.— -  Until  within  about  ten  years 
all  interior  plastering  used  in  this  country  was  made  of  quicklime, 
sand  and  hair. 

There  can  be  no  question  but  that  plaster  made  of  a  good  quality  of 
lime,  thoroughly  slaked  and  mixed  in  the  proper  manner,  is  very  dur- 
able and  also  a  valuable  sanitary  agent.  Most  of  the  lime  plaster  used 
at  the  present  day,  however,  is  very  poorly  and  cheaply  made,  often 
of  poor  materials,  and  very  much  of  it  is  far  from  durable. 

The  stones  from  which  lime  is  made,  and  the  method  of  preparing 
it  for  the  market,  are  described  in  Sections  100  and  154. 

Materials  for  making  lime  are  found  in  nearly  every  State  in  the 
Union,  but  as  no  two  quarries  of  stone  are  exactly  alike,  there  is  a 


328  BUILDING  CONSTRUCTION. 

great  difference  in  the  quality  of  limes  from  different  stones.  In  some 
localities,  also,  lime  is  obtained  from  shells  and  marble. 

The  manner  of  working  the  lime  also  varies  in  different  localities. 

In  New  England  and  New  York  lime  is  generally  put  up  in  casks 
or  barrels  and  sold  by  measure,  but  in  many  of  the  Western  States  it 
is  sold  loose,  like  coal,  and  by  weight. 

There  are  some  limes  which,  while  good  enough  for  making  ordi- 
nary mortar,  are  not  suitable  for  making  plaster ;  this  is  because  all 
the  particles  of  the  lime  do  not  immediately  slake.  Some  of  the  par- 
ticles, because  they  are  over-burned  or  for  some  other  reason,  will 
not  slake  with  the  bulk  of  the  lime,  but  continue  to  absorb  moisture, 
and  finally  after  a  long  period,  extending  sometimes  over  two  years, 
they  will  slake  or  "  pop  "  and  cause  a  speck  of  plaster  to  fall  off. 

The  author  has  seen  walls  and  ceilings  that  were  pitted  all  over 
from  this  cause. 

It  is  therefore  important  that  the  architect,  when  building  in  a  new 
locality,  or  upon  commencing  his  practice,  should  make  inquiries  as 
to  the  slaking  qualities  of  the  lime  at  hand,  and  where  more  than  one 
lime  is  available,  which  one  is  the  best.  In  some  localities  four  or 
five  different  qualities  of  lime,  from  as  many  different  places,  are 
found  on  the  market,  and  in  such  cases  the  architect  should  be  very 
careful  to  specify  the  particular  lime  which  he  considers  best. 
[Limes  are  generally  known  by  the  name  of  the  locality  where  they 
are  quarried.]  Even  in  the  best  limes  some  particles  do  not  slake 
quite  as  quickly  as  others,  and  it  is  not  generally  safe  to  apply  any 
plastering  in  which  the  lime  has  not  been  slaked  from  ten  days  to  two 
weeks. 

Sand,  for  plastering,  should  be  angular,  not  too  coarse  nor  too  fine, 
and  free  from  dust  and  all  foreign  substances.  Methods  of  testing 
sand  for  foreign  substances  were  described  in  Section  103. 

To  make  the  very  best  plaster,  the  sand  should  be  screened,  washed 
and  dried;  sand  prepared  in  this  way  can  sometimes  be  obtained  in 
the  larger  cities,  but  in  most  work  the  sand  is  merely  screened. 

Of  unprepared  sand,  river  sand  is  generally  the  best,  as  it  is  less 
likely  to  contain  impurities.  Pit  sand  is  very  apt  to  contain  clay. 

Sea  sand  is  less  angular  than  other  sands,  and  is  also  considered 
'objectionable  on  account  of  the  salt  contained  in  it.  It  should  never 
be  used  without  thorough  washing  in  fresh  water.  All  sands  require 
careful  screening  to  take  out  the  coarse  particles,  and  sand  for  hard 
finish  should  be  passed  through  a  sieve. 

Although  the  use  of  sand  in  mortar  is  principally  to  prevent  shrink- 


LATHING  AND  PLASTERING.  329 

ing  and  reduce  the  quantity  of  lime,  it  is  also  considered  to  have  a 
valuable  chemical  function,  causing  the  formation  of  a  hard  silicate 
of  lime,  which  pervades  and  strengthens  the  plaster. 

Hair  and  Fibre. — To  make  the  coarse  plaster  hang  together  better, 
hair  or  fibre  should  be  mixed  with  the  mortar  for  the  ground  work. 

Outside  of  a  few  of  the  large  Eastern  cities  hair  is  almost  entirely 
used  for  this  purpose.  For  several  years  Manilla  fibre,  chopped 
about  2  inches  long,  has  been  used  instead  of  hair  for  ordinary  mor- 
tar in  New  York  City  and  vicinity.  Most  of  the  patent  mortars  contain 
either  asbestos  or  Manilla  fibre.  Fibre  is  cleaner  than  hair,  and  is 
said  to  be  less  injured  by  the  lime. 

Most  of  the  hair  used  by  plasterers  is  taken  from  the  hides  of  cat- 
tle, and  is  washed  and  dried  and  put  up  in  paper  bags,  each  bag 
being  supposed  to  contain  one  bushel  of  hair  after  it  is  beat  up. 

The  weight  is  generally  given  as  7  or  8  pounds,  but  it  often  falls 
much  short  of  this. 

If  obtained  from  a  local  tannery,  the  hair  should  be  thoroughly 
washed  and  separated  before  using. 

Hair  is  generally  described  in  the  specifications  as  "  best  quality 
of  clean,  long  cattle  hair,"  but  the  plaster  must  take  it  as  it  comes  in 
the  bags. 

Goat  hair  is  used  to  some  extent  in  the  Eastern  States.  It  is 
longer  and  of  a  better  quality  than  cattle  hair. 

339.  Mixing  Mortar  for  Plastering.— The  proper  mixing  of 
lime  mortar  is  nearly  as  important  as  the  quality  of  the  lime.  The 
tendency  to  reduce  the  cost  of  building  to  the  lowest  possible  point, 
and  to  shorten  the  time  required  for  the  various  operations,  has,  with 
other  influences,  led  to  much  neglect  in  the  mixing  of  mortar,  and  it 
is  safe  to  say  that  three-quarters  of  the  lime  plaster  used  at  the  pres- 
ent time  is  not  properly  mixed. 

Where  mortar  is  mixed  by  hand  at  the  site  of  the  building,  the  fol- 
lowing method  is  probably  the  best  that  can  be  considered  as 
practicable  : 

First  the  lime  should  be  thoroughly  slaked  in  a  tight  box,  or,  if  the 
lime  is  not  pure,  so  that  a  residue  is  left  after  slaking,  it  should  be 
run  off  through  a  wire  sieve  into  another  box  and  allowed  to  stand 
for  from  twenty-four  hours  to  seven  days. 

Second.  After  the  lime  has  been  slaked  the  required  length  of  time 
the  hair  should  be  beat  up  and  thoroughly  incorporated  with  the  lime 
paste  with  a  hoe,  and  the  proper  amount  of  sand  then  added  and  the 
mixture  thrown  into  a  pile. 


330  BUILDING  CONSTRUCTION. 

Third.  After  the  mortar  has  stood  in  the  pile  not  less  than  seven 
days,  it  should  be  wet  up  with  water  to  the  proper  consistency  in 
small  quantities  and  immediately  applied  to  the  lathing  or  brickwork. 

The  ordinary  method  of  mixing  plastering  mortar  is  to  mix  the  hair 
and  sand  with  the  lime  as  soon  as  it  is  slaked,  and  then  throw  the 
mortar  into  a  pile,  the  whole  process  occupying  but  one  or  two  hours. 
The  objection  to  this  method  is  that  the  lime  does  not  always  get 
thoroughly  slaked,  and  the  hot  lime  and  the  steam  caused  by  the 
slaking  burn  or  rot  the  hair  so  as  almost  to  destroy  its  function  of 
strengthening  the  plaster.  For  all  good  work  the  architect  should 
specify  that  the  lime  be  slaked  at  least  twenty-four  hours  before 
working  in  the  hair. 

For  U.  S.  Government  work  the  hair  is  not  mixed  in  until  the  mor- 
tar is  wet  up  for  putting  on,  which  is  still  better,  but  rather  more 
expensive. 

If  the  mortar  is  required  in  freezing  weather  it  should  be  made 
under  cover,  and  under  no  circumstances  should  the  architect  permit 
the  use  of  mortar  that  ha>  been  frozen.  . 

The  mixing  of  mortar  in  basements,  although  sometimes  found 
necessary,  is  not  desirable,  as  it  introduces  much  moisture  into  the 
building.  Mortar  should  never  be  made  in  the  building  when  practi- 
cable to  avoid  it. 

340.  Machine-made  Mortar. — In  New  York  City,  Philadel- 
phia, and  possibly  some  other  places,  mortar,  both  for  bricklaying  and 
plastering,  is  now  made  by  machinery  in  buildings  specially  arranged 
for  the  purpose,  and  delivered  at  the  work  in  cart  load  lots  in  a  wet 
and  plastic  condition,  with  the  hair  or  fibre,  and  fresh  water  incor- 
porated with  the  lime  and  sand,  ready  for  use,  without  the  addition 
of  any  other  material  or  further  manipulation  whatever. 

The  advantages  of  having  the  mortar  made  in  this  way  are  that 
ample  time  is  given  the  lime  to  slake,  the  hair  and  sand  are  not  mixed 
•with  the  lime  until  just  before  delivery,  and  the  mixing  is  much  more 
thoroughly  and  evenly  done  by  machinery  than  is  possible  by  hand. 

Using  mortar  mixed  at  some  other  place  than  in  the  building  per- 
mits of  finishing  the  lower  stories  sooner  than  could  otherwise  be 
done,  and  also  does  away  with  the  inconvenience  of  having  a  large 
pile  of  mortar  stacked  on  the  sidewalk  or  in  the  basement. 

Machine-made  mortar  was  used  in  the  Corn  Exchange,  the  Man- 
hattan Life  Building,  the  Home  Life  Insurance  Building,  and  many 
cthtr  large  buildings  in  New  York. 


LATHING  AND  PLASTERING.  331 

The  process  of  making  the  mortar  in  the  Philadelphia  plant  is 
described  as  follows : 

Into  four  slacking  machines  or  revolving  pans,  about  twelve  bushels  of  lime  are 
placed  and  enough  water  introduced  to  slack  without  burning.  The  pan  is  started 
and  the  lime  is  kept  in  motion  by  a  mechanical  arrangement  consisting  of  three  feet 
on  a  perpendicular  shaft.  When  the  slacking  is  complete  a  plug  is  removed,  and 
the  lime  and  water  carried  by  a  trough  through  three  screens  into  a  well ;  from  this 
well  it  is  pumped  into  vats  located  in  the  upper  floors  of  the  mixing  house.  Screen- 
ing the  lime  eliminates  all  core  or  underburnt  limestone,  stones  and  other  foreign 
matter  so  injurious  to  mortar,  especially  that  used  by  plasterers. 

When  the  lime  and  water  is  pumped  into  the  vats  it  much  resembles  thick  milk, 
which,  after  standing  three  weeks,  assumes  the  consistency  of  soft  cheese.  Water  is 
allowed  to  stand  in  these  vats,  which  further  aids  in  the  slacking  of  any  minute  par- 
ticles that  have  escaped  through  the  sieves,  and  also  to  prevent  the  air  from  reaching 
it.  (The  lime  used  contains  a  considerable  amount  of  magnesia,  a  pure  carbonate 
not  giving  the  setting  qualities  desirable.) 

When  mortar  is  to  be  made  this  lime  paste  is  carried  to  the  mixing  pans,  which 
are  like  those  used  in  slacking,  with  the  exception  that  they  have  two  sets  of  feet ; 
sharp,  clean  bar  sand  is  also  placed  in  the  pans,  and  the  machine  thoroughly  incor- 
porates the  lime  and  sand  into  a  homogeneous  mass,  not  a  streak  of  lime  and  a  streak 
of  sand,  but  a  material  of  uniform  evenness.  As  a  result  of  this  care,  I  have  tested 
brickquetts  made  of  machine  mortar  and  have  obtained  as  great  a  tensile  strain  as  52 
pounds  to  the  square  inch  ;  in  twenty-seven  or  twenty-eight  days,  out  of  three  brick- 
quetts broken,  I  secured  48,  52  and  50  pounds  tensile  strain.  We  never  allow  lime 
to  air  slack  ;  neither  do  we  mix  the  sand  with  the  hot  lime  and  allow  it  to  stand.* 

When  mixing  mortar  by  hand,  the  nearer  the  process  approaches 
the  above  the  better  will  be  the  quality  of  the  plastering. 

341.  Proportion  of  Materials. — It  has  been  found  by  repeated 
experiments  that  a  barrel  of  Rockland  lump  lime,  thoroughly  slaked, 
will  yield  on  an  average  2.72  barrels  of  lime  paste.  Some  limes  will 
yield  more  and  others  less,  the  average  of  four  Eastern  limes  tested 
being  2.62  barrels  of  paste.  It  has  also  been  demonstrated  by 
repeated  experiments  that  the  average  sum  of  voids  in  sharp,  clean, 
silicious  bank  or  pit  sand,  taken  from  different  locations  and  thor- 
oughly screened,  is  .349  of  its  bulk.  It  was  also  shown  that  the  best 
mortar  is  obtained  by  mixing  with  the  sand  such  an  amount  of  lime 
paste  as  will  be  from  45  to  50  per  cent,  greater  than  the  amount 
needed  to  fill  the  voids  of  the  sand,  which  practically  requires  a  pro- 
portion of  i  part  lime  paste  to  2  of  sand.  This  is  the  proportion 
usually  specified  on  Government  work. 

As  it  is  difficult  to  measure  the  lime  paste,  it  would  perhaps  be 
better  to  specify  that  only  5  \  barrels  of  screened  sand  should  be  used 


Henry  Longcope,  in  the  Brickbuilder. 


332 


BUILDING  CONSTRUCTION. 


to  one  cask  of  lime.  Where  lime  is  sold  by  weight  about  the  same 
proportions  will  be  obtained  by  specifying  2\  barrels  of  sand  to  ioa 
pounds  of  dry  lime. 

Mixed  in  the  above  proportions  it  will  require  about  2\  casks,  or 
500  pounds,  of  lime  and  14  barrels  (42  cubic  feet)  of  sand  to  cover 
ico  yards  of  lath  work,  \  inch  thick  over  the  lath. 

The  proportion  of  hair  to  lime  should  be  for  first-class  work,  ij- 
bushels  of  hair  to  one  cask,  or  200  pounds,  of  lime  for  the  scratch 
coat,  and  £  bushel  of  hair  to  one  cask  of  lime  for  the  brown  coat. 
This  is  considerably  more,  however,  than  will  be  found  in  most 
plaster. 

The  proportion  of  lime  given  above  is  none  too  rich  for  first-class, 
plaster,  either  for  the  brown  or  scratch  coat,  but  it  is  seldom,  if  ever, 
that  brown  mortar  is  made  as  rich  as  this,  and  much  first-coat  work 
is  inferior  to  it. 

In  fact,  it  is  almost  impossible  to  regulate  the  proportion  and  uni- 
form mixing  of  common  plaster.  Where  lime  is  sold  by  the  cask  it 
can  be  done  by  mixing  one  cask  of  lime  at  a  time  and  measuring  the 
sand,  but  where  lime  is  sold  by  weight  it  would  be  necessary  to  keep 
scales  on  the  ground  for  weighing  the  lime  ;  and  in  either  case  it 
would  be  necessary  to  have  an  inspector  to  watch  the  making  of  the 
mortar. 

In  practice  the  lime  is  slaked  and  as  much  sand  mixed  with  it  as 
the  mortar  mixer  thinks  best  or  the  plaster  will  stand,  and  it  is  almost 
impossible  for  the  architect  to  tell  whether  or  not  there  is  too  much 
sand.  It  seldom  happens  that  there  is  too  little  sand. 

After  considerable  experience  with  mortar,  one  can  tell  something 
about  its  quality  by  its  appearance  when  wet  up,  or  by  trying  it  with 
a  trowel,  but  practically  the  architect  and  owner  is  in  most  cases  at 
the  mercy  of  the  contractor,  and  about  the  best  that  can  be  done, 
when  using  common  plaster,  is  to  insist  on  the  best  materials,  mixing 
in  the  hair  after  the  lime  is  cool  and  giving  the  contract  to  an  honest 
and  intelligent  plasterer. 

342.  Putting  On. — Plastering  .on  lathed  work  is  generally  done 
in  three  coats.*  The  first  coat  is  called  the  scratch  coat ;  the  second 
the  brown  coat ;  and  the  third,  the  white  coat,  skim  coat  or  finish. 

On  brick  or  stone  work  the  scratch  coat  is  generally  omitted. 


*  In  the  Eastern  States  dwellings  of  moderate  cost  are  generally  plastered  with  two-coat  work, 
the  first  or  scratch  coat  being  brought  out  nearly  to  the  grounds,  and  carefully  straightened  to- 
receive  the  skim  coat. 


LATHING  AND  PLASTERING.  333 

The  scratch  coat  should  always  be  made  "  rich,"  and  should  con- 
tain plenty  of  hair  or  fibre,  as  it  forms  the  foundation  for  the  brown 
and  white  coats.  This  coat  is  generally  put  on  from  ^  to  £  inch 
thick  over  the  laths,  and  should  be  pressed  by  the  trowel  with  suffi- 
cient force  to  squeeze  it  between  and  behind  the  laths,  so  as  to  form 
a  key  or  "  clinch."  It  is  this  key  which  holds  the  plaster  to  the  laths. 
When  the  first  coat  has  commenced  to  harden  (the  time  varying  from 
two  to  four  days)  it  should  be  scored  or  scratched  nearly  through  its 
thickness  with  lines  diagonally  across  each  other,  about  2  to  3  inches 
apart.  This  gives  a  better  hold  to  the  second  coat. 

The  first  coat  should  be  thoroughly  dry  before  putting  on  the  sec- 
ond coat,  but  if  the  surface  is  too  dry  it  should  be  slightly  dampened 
with  a  sprinkler  or  brush  as  the  second  coat  is  put  on. 

A  great  deal  of  plastering  (sometimes  called  "green  work")  is 
done  where  the  brown  coat  is  applied  from  the  same  stage,  and  as 
soon  as  the  scratch  coat  is  put  on.  When  done  in  this  way  the  scratch 
coat  is  generally  made  very  rich  and  the  brown  coat  largely  of  sand, 
the  brown  coat  being  worked  into  the  scratch  coat  so  that  it  really 
makes  only  one  coat. 

All  intelligent  plasterers  admit  that  it  makes  better  work  to  let  the 
scratch  coat  get  dry  before  the  brown  is  put  on,  but  as  it  takes  more 
labor  and  also  more  lime  to  put  on  the  plaster  in  this  way,  they  will 
not  do  it  unless  it  is  particularly  specified.  Besides  not  giving  as 
good  a  wall,  applying  the  brown  coat  to  the  green  scratch  coat  also 
causes  the  laths  to  swell  badly,  which,  when  they  dry,  causes  cracks 
in  the  plastering. 

The  second  or  "  brown  "  coat  is  put  on  from  \  to  |  inch  thick. 
With  this  coat  all  the  surfaces  should  be  brought  to  a  true  plane,  the 
angles  made  straight,  the  walls  plumb  and  the  ceilings  level. 

On  the  walls  the  plastering  can  generally  be  brought  to  a  true  plane 
by  means  of  the  grounds,  if  the  latter  are  set  true  and  the  wall  is  not 
too  large  or  without  openings.  On  the  ceilings,  however,  there  is 
usually  nothing  to  guide  the  plasterer  in  his  work,  and  the  conse- 
quence is  that  most  ceilings,  particularly  in  domestic  work,  have  a 
rolling  surface,  as  can  be  detected  at  the  edges  of  the  ceiling. 

Screeds. — The  only  way  of  obtaining  a  true  plane  on  ceilings  and 
on  walls,  where  the  grounds  are  not  sufficient,  is  by  screeding,  which 
is  done  by  applying  horizontal  strips  of  plaster  mortar,  6  to  8  inches 
wide  and  from  2  to  4  feet  apart,  all  around  the  room.  These  are 
made  to  project  from  the  first  coat  out  to  the  intended  face  of  the 
second  coat,  and  while  soft  are  made  perfectly  straight  and  out  of 


334  BUILDING  CONSTRUCTION. 

wind  with  each  other  by  measuring  with  a  plumb,  straight-edge,  etc. 
When  dry  the  second  coat  is  put  on,  filling  up  the  broad  horizontal 
spaces  between  them,  and  is  readily  brought  to  a  perfectly  flat  sur- 
face corresponding  with  the  screeds  by  long  straight-edges  extending 
over  their  surface. 

On  lathed  work,  if  the  studding  or  furrings  have  been  properly  set, 
screeding  should  not  be  necessary  except  on  ceilings,  but  on  brick  or 
stone  walls  it  is  impossible  to  get  true  surfaces  except  by  means  of 
grounds  or  screeds.  Screeding  was  formerly  done  much  more  exten- 
sively than  at  present ;  now  it  is  seldom  required  except  in  very 
expensive  buildings.  Screeding  can  be  done  only  in  three-coat  work. 
Before  the  brown  coat  becomes  hard  it  should  be  lightly  run  over 
with  the  scratcher  to  make  the  third  coat  adhere  better.  If  part  of 
the  walls  are  to  be  plastered  on  brickwork  and  part  on  laths,  the 
scratch  coat  is  put  only  on  the  laths,  and  when  this  is  dry  the  brown 
coat  is  spread  over  the  whole,  including  the  brickwork.  Brick  walls 
that  are  to  be  plastered  should  have  the  joints  left  rough  or  open,  and 
the  walls  should  be  brushed  clean  of  all  dust  and  slightly  dampened 
before  putting  on  the  mortar.  In  very  dry  weather  the  brick  walls 
should  be  sprinkled  with  a  hose  just  before  plastering. 

343.  Third  or  Finishing  Coat. — The  method  of  finishing  the 
wall  varies  somewhat  in  different  parts  of  the  countrv,  and  also  with 
the  kind  of  surface  desired.  In  some  localities,  particularly  in  small 
villages,  when  the  walls  are  to  be  papered,  no  finishing  coat  is  applied, 
but  the  brown  or  scratch  coat  is  smoothly  troweled.  This  reduces 
the  expense  but  a  trifle  and  is  not  to  be  recommended,  as  the  walls 
cannot  be  as  well  straightened  and  the  roughness  of  the  plaster  will 
show  through  the  paper. 

Skim  Coat. — In  many  of  the  Eastern  States  the  finishing  coat  is 
called  the  skim  coat,  and  is  made  of  lime  putty  and  a  fine  white  sand — 
generally  washed  beach  sand.  The  lime  is  slaked  and  run  through 
a  sieve  into  a  tight  box,  and  there  allowed  to  stand  until  it  becomes 
of  the  consistency  of  putty,  when  it  is  taken  out  and  the  sand  mixed 
with  it.  The  box  containing  the  putty  should  be  kept  covered  to 
keep  out  dust  and  dirt,  and  the  putty  should  not  be  used  until  at  least 
a  week  old. 

The  skim  coat  is  put  on  with  a  trowel,  floated  down,  and  then  gone 
over  with  a  brush  and  small  trowel  until  the  surface  becomes  hard 
and  polished.  In  the  author's  opinion  this  makes  a  much  better 
finish  than  the  ordinary  white  coat,  although  it  is  claimed  that  the  lat- 
ter is  better  for  walls  that  are  to  be  painted. 


LATHING  AND  PLASTERING.  335 

White  Coat.— (This  term  is  generally  used  to  designate  the  finish- 
ing coat  when  plaster  of  Paris  is  mixed  with  the  lime  putty.)  In 
most  portions  of  the  United  States  it  appears  to  be  the  custom  to 
finish  the  walls  with  a  thin  coat  of  lime  putty,  plaster  of  Paris  and 
marble  dust.  This  makes  a  whiter  wall  than  the  skim  coat,  and  if 
marble  dust  is  used  and  the  work  is  well  troweled  it  will  take  a  good 
polish.  Without  the  marble  dust  it  will  not  be  as  hard  nor  take  a 
polish.  For  this  work  the  lime  is  slaked  and  permitted  to  form  a 
putty,  as  with  the  skim  coat.  The  plaster  and  marble  dust  should 
not  be  mixed  with  the  putty  until  a  few  moments  before  using,  and 
then  only  as  much  should  be  prepared  as  can  be  used  up  at  once,  for 
if  left  to  stand  any  length  of  time  it  will  "  set  "  and  become  useless. 
It  should  be  finished  by  brushing  down  with  a  wet  brush  and  imme- 
diately going  over  it  with  a  trowel.  The  more  it  is  troweled  the 
harder  it  will  become.  In  estimating  the  quantity  of  materials 
required  for  the  white  coat,  90  pounds  of  lime,  50  pounds  of  plaster 
and  50  pounds  of  marble  dust  should  be  allowed  to  100  square  yards. 

Sand  Finish. — When  a  rough  finish  is  desired  for  fresco  work,  as 
in  churches,  halls,  etc.,  the  third  coat  is  mixed  with  lime  putty  and 
sand  as  for  skim  coat,  except  that  coarser  sand  and  a  greater  quan- 
tity of  it  is  used.  Sometimes  a  small  quantity  of  plaster  of  Paris  is 
also  mixed  with  it.  Sand  finish  should  be  applied  before  the  brown 
coat  is  quite  dry,  and  should  be  floated  with  either  clear,  soft  pine  or 
cork-faced  floats.  The  roughness  of  the  surface  desired  may  be 
conveniently  designated  by  comparing  it  with  the  different  grades  of 
sand  paper. 

Sometimes  the  brown  coat  is  floated  to  give  an  imitation  of  sand 
finish,  but  it  is  impossible  to  get  an  even  and  uniform  surface  without 
using  a  separate  coat.  Sand  finish  is  often  ruled  off  and  jointed  to  im- 
itate stone  ashlar.  It  may  also  be  colored  as  described  on  page  356. 

HARD  WALL  PLASTERS. 

344.  By  using  only  the  best  materials  and  mixing  them  in  the  man- 
ner described  it  is  possible  to  obtain  a  very  good  quality  of  wall  plas- 
ter, but  there  are  so  many  chances  of  getting  an  inferior  job  when 
ordinary  lime  plaster  is  used,  that  a  material  which  can  be  used  with 
greater  certainty  is  very  much  to  be  desired.  Such  a  material 
appears  to  be  found  in  the  improved  wall  plasters  recently  placed  on 
the  market. 

There  are  now  several  improved  plasters  manufactured  by  different 


336  BUILDING  CONSTRUCTION. 

companies  which,  although  differing  in  their  composition,  apparently 
give  about  the  same  kind  of  wall. 

The  general  name  given  to  these  improved  or  patented  wall  plas- 
ters is  that  of  "hard  wall  plaster"  .or  mortar. 

There  are  two  distinct  classes  of  hard  plasters,  which  may  be  des- 
ignated as  natural  cement  plasters  and  chemical  or  patented  plasters. 

Natural  Cement  Plasters. — In  this  class  are  the  Acme,  Aga- 
tite,  Aluminite,  Climax  and  Royal,  the  first  and  last  names  being  per- 
haps the  best  known. 

The  earth  from  which  these  plasters  are  produced  is  found  in 
various  portions  of  Kansas  and  Texas.  It  is  of  a  light  ash-gray  color 
and  of  about  the  consistency  of  hard  plastic  clay,  which  it  much 
resembles  in  appearance,  although  its  chemical  nature  is  more  like 
that  of  gypsum. 

When  calcined  it  assumes  a  pulverized  form.  When  mixed  with  water  it  sets  like 
hydraulic  lime  or  cement,  but  much  more  slowly,  so  that  ample  time  is  afforded  for 
applying  the  mortar. 

A  sample  of  agatite,  after  several  weeks  setting,  broke  under  a  tensile  strength  of 
370  pounds  per  square  inch.  It  is  superior  in  strength  to  most  of  the  hydraulic  limes 
and  natural  cements.* 

The  various  deposits  from  which  the  plasters  above  mentioned  are 
produced  appear  to  be  of  about  the  same  grade  of  earth,  the  plasters 
differing,  if  at  all,  only  in  their  strength  and  working  qualities,  which 
is  due  principally  to  slight  differences  in  the  process  of  manufacture. 

The  Acme  cement  plaster  is  produced  by  calcining  the  natural 
earth  at  a  high  degree  of  heat  (about  600°  Fahr.),  which  rids  the 
material  of  not  only  the  free  moisture,  but  also  the  combined 
moisture. 

The  resulting  plaster  is  slow  setting,  works  smooth  under  the  trowel, 
and  does  not  come  to  its  normal  strength  until  thirty  or  sixty  days 
after  it  is  spread. 

These  cement  plasters  are  remarkable  for  their  great  adhesive 
quality.  They  will  stick  firmly  to  stone,  brick  or  wood  without  the 
aid  of  hair  or  fibre.  Acme  cement  has  been  used  to  some  extent  in 
New  York  for  setting  fireproof  tiling,  and  has  been  found  superior 
for  this  purpose  to  the  ordinary  natural  cements. 

Acme  cement  plaster  was  the  first  of  this  class  to  be  put  on  the 
market.  It  has  been  extensively  used  throughout  the  country,  and 
makes  a  very  superior  wall  plaster.  Large  quantities  of  it  were  used 
in  plastering  the  World's  Fair  buildings,  Chicago.  Agatite  and 

*  Professor  Edwin  Walters,  in  Kansas  City  Journal,  January  20,  1893. 


LATHING  AND  PLASTERING.  337 

Royal,  although  more  recently  introduced,  have  also  been  quite 
extensively  used,  particularly  on  large  and  important  buildings  in  the 
West.  Climax  is  produced  especially  for  the  Southern  trade. 

345.  Chemical  or  Patented  Plasters.— In  this  class  are: 
King's  Windsor  Cement  dry  mortar,  Adamant,  Rock  Wall,  Granite, 
and  some  others  not  so  well  known. 

The  precise  composition  of  these  plasters  is  kept  secret,  but  it  is 
generally  understood  that  they  are  made  from  gypsum  (plaster  of 
Paris  calcined  at  about  225°  of  heat),  to  which  some  material  or 
chemical  is  added  to  retard  the  natural  quick  setting  of  the  plaster 
of  Paris  and  make  it  slow  enough  setting  that  it  can  be  mixed  with 
sand  and  spread  upon  the  wall.  As  well  as  the  author  has  been  able 
to  discover  the  facts,  the  difference  in  these  patented  plasters  is  due 
principally  to  the  chemical  or  other  material  used  for  the  retarder. 

The  first  of  these  plasters,  and  the  first  of  all  hard  plasters  placed 
on  the  market,  was  Adamant.  This  material  was  first  introduced  as 
a  substitute  for  lime  plaster  at  Syracuse,  N.  Y.,  in  1886.  It  is  a 
chemical  preparation,  and  the  manufacture  of  the  chemicals  is  cov- 
ered by  patents.  The  chemicals  are  manufactured  exclusively  at 
Syracuse,  N.  Y.,  by  the  original  company  and  sold  to  licensed  com- 
panies, who  prepare  and  sell  the  plaster.  There  are  twenty  or  more 
of  these  branch  companies  scattered  throughout  the  country.  The 
Adamant  companies  claim  that  the  quality  of  their  plaster  is  due 
principally  to  the  chemicals  used  in  its  preparation.  Adamant  has 
been  more  extensively  used  up  to  this  date  (1896)  than  any  other  of 
the  hard  wall  plasters. 

The  Windsor  Cement  dry  mortar  is  made  by  mixing  certain  chem- 
icals with  Nova  Scotia  gypsum  of  a  superior  quality  to  form  the 
cement,  and  the  mortar  is  made  by  mixing  with  the  cement  washed 
and  kiln-dried  pit  sand  and  asbestos  fibre,  all  the  materials  being 
accurately  weighed  and  uniformly  mixed  by  special  machinery.  The 
mortar  is  made  in  the  vicinity  of  New  York  City.  It  has  been  exten- 
sively used  in  many  of  the  best  buildings  recently  built  in  that  city, 
and  to  a  considerable  extent  elsewhere. 

A  preparation,  presumably  of  this  class,  called  Granite  Hard  Wall 
Plaster,  is  made  in  Minneapolis,  and  similar  preparations  are  made  by 
local  companies  in  several  localities. 

As  far  as  the  author  has  been  able  to  ascertain  all  of  these  mate- 
rials give  good  results  when  properly  handled,  although  those  which 
have  been  longest  on  the  market  are  apt  to  be  the  most  reliable. 


338  BUILDING  CONSTRUCTION. 

346.  How  Sold. — All  of  the  plasters  above  described  are  packed 
in  sacks,  or  bags,  holding  either  100  pounds  or  a  half  barrel  each. 

Acme,  Agatite  and  Royal  are  sold  in  the  form  of  cement  only,  and 
the  sand  is  mixed  with  the  cement  as  it  is  used  by  the  plasterer. 

Two  kinds  of  cement  are  sold,  one  mixed  with  fibre  and  known 
as  fibred  cement,  and  the  other  without  fibre.  The  fibred  cement 
should  be  used  for  the  first  coat  on  lathed  work,  whether  of  wood  or 
metal.  On  brickwork,  or  fireproof  tiling,  fibre  is  not  required,  and 
the  unfibred  cement  should  be  used. 

The  unfibred  cement  is  also  used  for  second  or  brown  coat  and 
wherever  the  plaster  is  to  be  troweled  down  to  a  smooth,  hard  sur- 
face. Where  the  plaster  is  to  be  finished  with  a  white  surface  it  'is 
necessary  to  use  lime  and  plaster  of  Paris  (as  on  lime  plaster)  over 
these  cements,  as  they  are  of  a  gray  color. 

Windsor  Cement  dry  mortar  and  Adamant  are  sold  mixed  with 
fibre  and  sand,  all  ready  for  applying  by  simply  mixing  with  clean 
water.  Two  grades  of  the  Windsor  mortar  are  made,  one  for  lath 
work  and  the  other  for  applying  on  iron,  brick,  terra  cotta,  etc.,  the 
only  difference  between  the  two  being  that  the  latter  contains  more 
sand  than  the  former.  Adamant  is  made  in  eight  different  grades 
for  base  coats  on  lath,  brickwork  or  tile,  for  browning  coat,  and 
for  finishing.  Four  different  kinds  of  finishing  material  are  made> 
to  give  any  style  of  finish  desired. 

347.  Application. — The  method  of  applying  these  plasters  does 
not  differ  materially  from  that  already  described  for  lime  mortar, 
except  that  the  second  (corresponding  to  the  brown)  coat  is  put  on 
directly  after  the  first  coat,  and  is  finished  with  the  darby  instead  of 
with  the  float.     Being  of  the  nature  of  cement,  or  plaster  of  Paris, 
these  mortars  set  instead  of  drying,  and  but  little  water  should  be 
used  in  working  them.     Only  as  much  material  should  be  mixed  as 
can  be  applied  in  one  and  a  half  hours,  and  material  that  has  com- 
menced to  set  should  never  be  remixed. 

Only  clean  water  should  be  used,  and  the  tools  and  mortar  box 
should  be  kept  perfectly  clean  and  the  box  cleaned  out  after  each 
mixing. 

When  using  the  hard  plasters  on  wood  laths,  the  laths  should  be 
thoroughly  dampened,  or  expanded,  before  the  plaster  is  spread,  so  that 
they  will  not  swell  after  the  plaster  has  commenced  to  set.  Brick, 
stone  and  tile  work  should  also  be  well  sprinkled  before  applying 
these  mortars. 


LATHING  AND  PLASTERING.  339 

Most  of  the  manufacturers  of  hard  plasters  recommend  that  when 
their  plaster  is  to  be  used  the  laths  be  spaced  only  from  \  to  \  inch 
apart,  and  that  J-inch  grounds  be  used,  claiming  that  a  less  quantity 
of  their  material  is  required  than  of  ordinary  lime  mortar. 

A  gentleman  who  has  had  much  experience  with  cement  plasters, 
however,  says  that  "  More  failures  are  made  in  using  hard  plaster  by 
using  too  thin  coats,  too  weak  keys  and  too  weak  material  (when  sold 
unmixed  with  sand)  than  from  any  other  cause. 

"  To  do  a  good  job  of  hard  plastering  it  is  necessary  to  use  a  suffi- 
cient amount  of  cement  to  give  it  tensile  strength,  a  good  wide  key, 
and  a  good  thick  coat  of  plaster.  Where  it  is  spread  very  thin  it  is 
sure  to  crack  and  give  an  unsatisfactory  wall." 

For  lath  work  a  better  wall  will  be  obtained,  although  at  a  little 
more  expense,  by  putting  on  |-inch  grounds  and  having  a  f -inch  key. 

All  of  these  plasters,  except  Adamant,  can  be  finished  with  a  third 
coat,  as  described  in  Section  343,  which  should  in  no  case  be  applied 
until  the  base  is  thoroughly  dry. 

Sand  finish  is  generally  made  by  mixing  sand  with  the  same  plaster 
as  is  used  for  the  brown  coat. 

Full  directions  for  applying  the  various  grades  of  these  plasters  are 
furnished  by  the  manufacturers,  and  architects  should  see  that  these 
instructions  are  carefully  and  faithfully  followed,  as  when  improperly 
applied  these  plasters  are  inferior  to  the  ordinary  lime  mortar. 

348.  Advantages. — The  principal  advantages  gained  by  the  use 
of  these  plasters  are  :  uniformity  in  strength  and  quality,  greater 
hardness  and  tenacity,  freedom  from  pitting,  less  weight  and  moisture 
in  the  building,  saving  in  time  required  for  making  and  drying  the 
plaster,  minimum  danger  from  frost  and  greater  resistance  to  fire  and 
water. 

Frost  does  not  harm  these  mortars  after  they  have  commenced  to 
set  or  the  chemical  action  has  taken  place.  When  used  in  freezing 
weather  they  must  not  be  allowed  to  freeze  during  the  first  thirty-six 
hours  after  applying  ;  after  that  time  frost  will  do  no  harm. 

Those  plasters  which  are  already  mixed  with  sand  and  fibre  also 
have  the  additional  advantage  of  thorough  and  uniform  mixing  of 
the  materials  and  absolute  correctness  of  proportion.  This  latter  advan- 
tage is  perhaps  most  appreciated  by  the  architect,  as  it  prevents  all 
chance  of  using  a  poor  quality  of  sand,  or  too  much  of  it,  and  saves 
him  a  great  deal  of  labor  in  the  superintendence. 


340  BUILDING  CONSTRUCTION. 

The  benefit  to  the  owner  in  using  these  plasters  consists  in  secur- 
ing much  more  substantial  walls  than  is  possible  with  the  ordinary 
hand-made  mortar,  less  risk  from  fire  and  less  expense  for  repairs. 

The  slight  additional  expense  of  using  them  is  hardly  to  be  consid- 
ered in  comparison  with  the  benefits  obtained,  and  it  is  probable  that 
these  plasters  will  in  a  short  time  become  generally  adopted,  they 
being  already  extensively  used  in  the  largest  and  most  costly  buildings. 

For  business  buildings  the  saving  in  the  time  required  in  drying 
the  plastering  will  more  than  pay  for  the  additional  expense. 

On  account  of  their  greater  density  these  mortars  will  not  harbor 
vermin  nor  absorb  noxious  gases  or  disease  germs,  and  are  therefore 
especially  desirable  for  hospitals,  schools,  etc.  Heat,  air  and  moist- 
ure will  not  pass  through  them  as  through  lime  plaster. 

A  wall  of  hard  plaster,  wood  or  metal  lath  is  also  much  more 
resonant  than  one  of  lime  mortar,  and  for  this  reason,  and  also  on 
account  of  their  greater  strength,  these  mortars  should  be  especially 
valuable  for  plastering  churches,  opera  houses  and  public  halls. 

STUCCO  WORK. 

349.  This  term,  as  commonly  used  in  this  country,  refers  to  orna- 
mental interior  plaster  work,  such  as  cornices,  mouldings,  centre- 
pieces, etc.  For  such  work  a  mixture  of  lime  paste  and  plaster  of 
Paris  is  used,  except  for  cast  work,  which  is  made  entirely  of  plaster 
of  Paris. 

Plaster  of  Paris  is  produced  by  the  gentle  calcination  of  gypsum  to 
a  point  short  of  the  expulsion  of  the  \\hole  of  the  moisture.  Paste 
made  from  it  sets  in  a  few  minutes,  and  attains  its  full  strength  in  an 
hour  or  two.  At  the  time  of  setting  it  expands  in  volume,  which 
makes  it  especially  valuable  for  taking  casts  and  for  making  cast 
ornaments  for  walls  and  ceilings,  and  also  for  patching  and  repairing 
ordinary  plaster  work. 

When  added  to  lime  mortar,  plaster  of  Paris  causes  the  mortar  to 
set  or  harden  very  quickly,  and  for  this  reason  it  is  often  mixed  with 
mortar  to  be  used  for  patching  or  repairing,  or  where  it  is  necessary 
to  have  the  plaster  harden  very  quickly.  When  this  is  done  it  is 
called  "  gauged  work." 

Plaster  of  Paris  is  very  liable  to  crack  when  used  clear  and  in  con- 
siderable thickness.  Cast  ornaments  made  of  it  are  therefore  usually 
made  hollow,  or  with  a  thin  shell.  For  work  that  is  to  be  run,  or 
worked  by  hand,  it  cannot  be  used  clear,  as  it  sets  too  quickly.  It  is 
for  this  reason  that  lime  putty  is  mixed  with  it. 


LATHING  AND  PLASTERING. 


34i 


For  mouldings,  cornices,  etc.,  about  2  parts  of  plaster  of  Paris  to  i 
of  lime  paste  is  used. 

Plain  mouldings,  whether  in  a  cornice,  centrepiece,  or  on  the  wall 
or  ceiling,  are  usually  "  run  "  in  place  by  hand.  The  process  con- 
sists in  placing  on  the  surface  of  the  wall  or  ceiling  a  sufficient  body 
of  plaster  and  forming  the  mould  by  running  along  it  a  sheet  iron 
template,  cut  to  the  reverse  profile  of  the  mould.  The  template  is 
stiffened  by  wooden  cleats,  and  provided  with  struts  to  keep  the  plane 
of  the  template  always  perpendicular  to  the  plane  of  the  surface  on 
which  the  mould  is  run.  The  stucco  work  is  always  run  before  the 


Furring  Blocks, 
luth. 


U.UUL 


tf^^ittop 

l*iS 


Fig.  232. 

finishing  coat  of  plaster  is  applied,  as  it  is  necessary  to  fasten  light  pine 
straight-edges  on  the  wall  to  form  guides  for  the  templates.  In  run- 
ning the  moulding  two  men  are  generally  required,  one  to  put  on  the 
plaster  as  it  is  needed  and  the  other  to  work  the  template,  which  gen- 
erally has  to  be  worked  back  and  forth  several  times  before  the 
moulding  is  finished. 

The  whole  moulding  or  cornice  between  any  two  breaks  or  pro- 
jections should  be  completed  at  once,  so  that  the  entire  length  may 
be  uniform  in  shape  and  shade. 

The  mitres  at  the  angles,  both  internal  and  external,  have  to  be 
finished  by  hand,  using  a  small  trowel  and  straight-edge. 


342 


B  UILDING  CONS  TR  UC  TION. 


If  the  cornice  or  moulding  contains  much  ornamental  work,  it 
is  cheaper  to  cast  it  in  sections  of  about  2  feet  in  length,  and  attach 
to  the  wall  by  means  of  liquid  plaster  of  Paris.  It  requires  great 
care  in  cast  work  to  have  the  sections  join  nicely,  so  that  the  mem- 
bers will  present  a  perfectly  straight  line. 

If  there  are  only  one  or  two  enriched  members,  the  rest  of  the 
moulding  or  cornice  may  be  run  in  the  usual  way,  leaving  sinkings  to 
receive  the  enriched  mem- 
bers, which  are  then  cast 
and  stuck  in  place,  as  at 

A,  Fig.  232. 

In    designing    cornices 
or   belt    mouldings,    care 

should  be  taken  not  to  have  over  3  inches  in  thickness 
of  plaster  at  any  point.  If  the  mouldings  have  greater 
than  this  the  wall  or  angle  should  be  blocked  and 
lathed,  as  in  Fig.  232,  so  as  to  reduce  the  amount  of 
plaster  required  to  a  minimum.  When  the  projection 
is  only  about  3^  or  4  inches,  the  back  may  be  formed 
of  brown  mortar  (Fig.  233),  containing  a  little  plaster 
of  Paris,  and  held  in  place  by  projecting  spikes  or 
large  nails,  driven  into  the  wall  or  ceiling  before  the 
mortar  is  put  on. 

Centre  ornaments,  when  consisting  only  of  plain  cir- 
cular  mouldings,  are  run  in  the  same  way  as  other 
moulded  work,  except  that  the  template  is  attached  to 
a  piece  of  wood  which  is  pivoted  at  the  centre  of  the 
ornament.  Enriched  centres  are  cast  in  a  mould  and 
stuck  to  the  ceiling  after  the  finish  coat  is  on. 

All   kinds  of  ornaments,  such  as  paneled  ceilings,        Fig 
bas-reliefs,  imitations  of  foliage,  etc.,  may  readily  be 
executed  in  plaster  of  Paris,  and  when  the  ornament  is  placed  in 
such  positions  that  it  cannot  readily  be  injured  by  objects  in  the 
room,  it  answers  as  well  as  harder  and  more  expensive  materials. 

Since  hard  wood  finish  has  become  so  prevalent,  however,  it  has 
largely  supplanted  the  plaster  cornices  that  were  so  common  fifty 
years  ago. 

Stucco  work  is  generally  included  in  the  plasterer's  specifications. 
As  it  is  much  more  expensive  than  ordinary  plastering,  the  quantity 
and  character  of  it  should  be  clearly  indicated  on  the  drawings  and 
in  the  specifications,  and  by  full  size  details. 


LATHING  AND  PLASTERING.  343 

For  enriched  work  the  architect  should  require  that  the  models  be 
approved  by  him  before  the  casts  are  made. 

350.  Keene's  Cement.— When  it  is  desired  to  finish  plaster 
walls,  ceilings,  columns,  etc.,  with  a  very  hard  and  highly  polished 
surface,  Keene's  cement  is  generally  used  for  the  finishing  coat. 
This  cement  is  a  plaster  produced  (in  England)  by  recalcining  plas- 
ter of  Paris  after  soaking  it  in  a  saturated  solution  of  alum.  This 
material  is  very  hard  and  capable  of  taking  a  high  polish,  and  walls 
finished  with  it  may  be  sponged  with  soft  water  without  injury. 

It  is  especially  valuable  for  finishing  plastered  columns,  the  lower 
portions  of  walls,  and  wherever  the  plaster  is  liable  to  injury  from  con- 
tact with  furniture,  etc.  It  is  also  used  in  the  manufacture  of  artifi- 
cial marble. 

The  manufacturers  of  King's  Superfine  Windsor  Cement  claim  that 
for  finishing  walls  it  is  equal  to  the  imported  Keene's  cement ;  it  is 
considerably  less  expensive. 

Neither  of  these  materials  should  be  used  in  situations  much 
exposed  to  the  weather,  on  account  of  their  solubility. 

351.  Scagliola  is  a  coating  applied  to  walls,  columns,  etc.,  to 
imitate  marble.  The  base  or  ground  work  is  generally  of  rich  lime 
mortar  containing  a  large  proportion  of  hair.  After  this  has  set  and 
is  quite  dry  it  is  covered  with  a  floated  coat,  consisting  of  plaster  of 
Paris  or  Keene's  cement,  mixed  with  various  coloring  matters  in  a 
solution  of  glue  or  isinglass,  to  give  greater  solidity  and  to  prevent 
the  plaster  of  Paris  from  setting  too  quickly.  When  the  surface  is 
thoroughly  hard  it  is  rubbed  with  pumice  stone  and  then  polished 
until  it  looks  like  polished  marble.  Columns  can  be  made  in  this 
way  that  can  hardly  be  detected  by  the  eye  from  marble. 

Imitation  marble,  when  in  flat  slabs,  is  commonly  made  on  sheets 
of  plate  glass.  Threads  of  floss  silk,  which  have  been  dipped  into 
the  veining  colors,  previously  mixed  to  a  semi-fluid  state  with  plaster 
of  Paris,  are  placed  upon  a  sheet  of  plate  glass  so  as  to  resemble  the 
veins  in  the  marble  to  be  imitated.  Upon  this  the  body  color  of  the 
marble  is  placed  by  hand.  The  silk  is  then  withdrawn  and  dry  plas- 
ter of  Paris  is  sprinkled  over  to  take  up  the  excess  of  moisture  and 
to  give  the  plaster  the  proper  consistency.  A  backing  of  cement  or 
plaster  of  Paris  is  then  applied  of  any  desired  thickness.  Canvas  is 
sometimes  placed  in  the  backing  to  give  greater  strength.  After 
removing  from  the  glass  the  slab  is  polished  and  set  in  place  in  the 
same  manner  as  the  genuine  material.  This  work  naturally  requires 
much  skill  in  the  workman,  besides  practice  and  experience 


344 


BUILDING  CONSTRUCTION. 


A  great  deal  of  scagliola  has  been  used  in  Europe,  and  in  recent 
years  several  companies  have  been  formed  in  America  for  making 
artificial  marble,  which  is  essentially  the  same  thing.  For  interior 
work  scagliola  should  be  as  durable  as  marble,  and  there  are  columns 
of  it  in  Europe  several  hundred  years  old.  It  should  not  be  used  on 
the  exterior  of  buildings,  as  it  will  not  bear  exposure  to  the  weather. 

352.  Fibrous  Plaster  consists  of  a  thin  coating  of  plaster  of 
Paris  on  a  coarse  canvas  backing  stretched  on  a  light  framework 
and  formed  into  slabs.     For  casts  about  \  inch  of  plaster  is  put  in 
the  mould,  and  the  canvas  is  then  put  on  the  back  and  slightly 
pressed  into  the  plaster.     Fibrous  plaster  is  very  light  and  strong, 
and  can  be  easily  handled  without  breaking.     It  is  extensively  used 
in  England  for  ornamental  work,  and  in  Brazil  it  is  said  to  be  used 
extensively  for  external  work. 

Carton  Pierre  is  a  material  used  for  making  raised  ornaments  for 
wall  and  ceiling  decoration.  It  is  composed  of  whiting  mixed  with 
glue  and  the  pulp  of  paper,  rags  and  sometimes  hemp,  which  is  forced 
into  plaster  or  gelatine  moulds,  backed  with  paper,  and  then  removed 
to  a  drying  room  to  harden.  It  is  much  stronger  and  lighter  than 
common  plaster  of  Paris  ornaments,  and  is  not  so  liable  to  chip  or 
break  if  struck  with  anything. 

Ornaments  of  carton  pierre  (under  different  names)  are  now  exten- 
sively used  in  this  country  for  decorating  rooms,  mantels,  etc.,  and 
also  to  some  extent  on  the  exterior  of  buildings.  If  kept  painted 
there  appears  to  be  no  reason  why  it  should  not  last  for  many  years, 
except  in  very  exposed  positions. 

EXTERNAL  PLASTERING. 

353.  This  is  generally  either  rough-cast  or  stucco.     The  first  is  a 
description  of  coarse  plastering,  generally  applied  on  laths  ;  the  sec- 
ond is  a  description   of  plastering  on  brickwork,  executed  so  as  to 
resemble  stone  ashlar. 

Rough-cast  has  been  extensively  used  in  Canada,  and  to  some 
extent  in  the  Northern  States.  It  is  said  to  be  much  warmer  than 
siding  or  shingles,  less  expensive,  and  quite  as  durable.  It  is  also 
more  fire-resisting. 

"  There  are  frame  cottages  near  the  city  of  Toronto  and  along  the 
northern  shores  of  Lake  Ontario  that  were  plastered  and  rough-casted 
exteriorly  over  forty  years  ago,  and  the  mortar  to-day  is  as  good  and 
sound  as  when  first  put  on,  and  it  looks  as  though  it  was  good  for 


LATHING  AND  PLASTERING.  345 

many  years  yet  if  the  timbers  of  the  building  it  preserves  remain 
good. 

"  It  is  quite  a  common  occurrence  in  Manitoba  and  the  northwest 
Territories  in  the  winter  to  find  the  mercury  frozen,  yet  this  intensity 
of  frost  does  not  seem  to  affect  the  rough-casting  in  the  least,  though 
it  will  chip  bricks,  contract  and  expand  timber  and  render  stone  as 
brittle  as  glass  in  many  cases."* 

Frame  buildings  to  be  rough-casted  should  be  covered  with  sheath- 
ing and  one  thickness  of  tarred  paper.  *  The  partitions  should  be  put 
in  and  even  lathed  before  the  outside  is  plastered,  as  it  is  important 
to  have  the  building  stiff  and  well  braced. 

The  best  mode  of  rough-casting,  as  practiced  in  the  lake  district  of 
Ontario,  is  said  to  be  as  follows  : 

Lath  over  the  sheathing  (or  tarred  paper  if  used)  diagonally  with  No.  i  pine  laths, 
keeping  i^  inches  space  between  the  lath  ;  nail  each  lath  with  five  nails  and  break 
joints  every  1 8  inches  ;  over  this  lath  diagonally  in  the  opposite  direction,  keeping 
the  same  space  between  the  laths  and  breaking  joint  as  before.  Careful  and  solid 
nailing  is  required  for  this  layer  of  lathing,  as  the  permanency  of  the  work  depends 
to  some  extent  on  this  portion  of  it  being  honestly  done.  The  first  coat  should  con- 
sist of  rich  lime  mortar,  with  a  large  proportion  of  cow's  hair,  and  should  be  mixed 
at  least  four  days  before  using.  The  operator  must  see  to  it  that  the  mortar  be  well 
pressed  into  the  key  or  interstices  of  the  lathing  to  make  it  hold  good.  The  face  of 
the  work  must  be  well  scratched  to  form  a  key  for  the  second  coat,  which  must  not  be 
put  on  before  the  first  or  scratch  coat  is  dry.  The  mortar  for  the  second  coat  is  made 
the  same  as  for  the  first  coat,  and  is  applied  in  a  similar  manner,  with  the  exception 
that  the  scratch  coat  must  be  well  damped  before  the  second  coat  is  put  on,  in  order 
to  keep  the  second  coat  moist  and  soft  until  the  dash  or  rough-cast  is  thrown  on. 

The  dash,  as  it  is  called,  is  composed  of  fine  gravel,  clean  washed  from  all  earthy 
particles  and  mixed  with  pure  lime  and  water  till  the  whole  is  of  a  semi-fluid  con- 
sistency. This  is  mixed  in  a  shallow  tub  or  pail  and  is  thrown  upon  the  plastered 
wall  with  a  wooden  float  about  5  or  6  inches  square.  While  the  plasterer  throws  on 
the  rough-cast  with  the  float  in  his  right  hand,  he  holds  in  his  left  a  common  white- 
wash brush,  which  he  dips  into  the  dash  and  then  brushes  over  the  mortar  and 
rough-cast,  which  gives  them,  when  finished,  a  regular  uniform  color  and  appearance. 

For  100  yards  of  rough  casting,  done  as  above  described,  the  following  quantities 
will  be  required  :  1,800  laths,  12  bushels  of  lime,  i£  barrels  best  cow  hair,  if  yards 
of  sand,  f  yard  of  prepared  gravel  and  16  pounds  of  cut  lath  nails,  I  j  inches  long. 
A  quarter  barrel  of  lime  putty  should  be  mixed  with  every  barrel  of  prepared  gravel 
for  the  dash.  The  dash  may  be  colored  as  desired  by  using  the  proper  pigments. 

To  color  100  yards  in  any  of  the  tints  named  herewith  use  the  following  quanti- 
ties of  ingredients  :  For  a  blue-black,  5  pounds  of  lampblack  ;  for  buff,  5  pounds  of 
green  copperas,  to  which  add  I  pound  of  fresh  cow  manure,  strained,  and  mixed  with 
the  dash.  A  fine  terra  cotta  is  made  by  using  15  pounds  of  metallic  oxide,  mixed 


Rough-Casting  in  Canada,"  by  Fred.  T.  Hodgson,  Architecture  and  Building,  March: 


346  BUILDING  CONSTRUCTION. 

with  5  pounds  of  green  copperas  and  4  pounds  of  lampblack.  Many  tints  of  these 
colors  may  be  obtained  by  varying  the  quantities  given.  The  colors  obtained  by 
these  methods  are  permanent  ;  they  do  not  fade  or  change  with  time  or  atmospheric 
variations.  Earthy  colors,  like  Venetian  red  and  umber,  soon  fade  and  have  a  sickly 
appearance. 

Expanded  metal,  perforated,  or  stiffened  wire  lathing  are  undoubt- 
edly better  than  wood  laths  for  external  plastering,  as  they  hold  the 
plaster  better  and  also  afford  greater  protection  from  fire. 

The  following  description  of  external  plastering,  as  used  by  an 
architect  of  considerable  experience  with  this  sort  of  work,  was  pub- 
lished in  the  Brickbuilder  for  August,  1895,  and  probably  represents 
the  best  current  practice  in  this  country  : 

I  have  always  used  three-coat  work,  the  first  well-haired  mortar  and  one-third 
Portland  cement,  added  when  ready  for  use  ;  this  coat  well  scratched.  The  second 
coat  the  same,  with  the  omission  of  the  hair,  and  the  third  coat  the  same  proportion, 
but  with  coarse  sand  or  gravel,  either  floated  or  put  on  slap-dash,  according  to  the 
kind  of  finish  I  wished  to  obtain. 

I  have  occasionally  used  a  very  small  quantity  of  ochre  in  this  last  coat,  but  it 
must  be  mixed  very  thoroughly  and  carefully  in  order  to  produce  an  even  color. 

This  plaster  work  I  have  used  on  wood  lath  over  stud  without  rough  boarding 
behind  it.  Also  on  rough  boarding  with  furrings  and  wood  lath,  which  is  better ; 
and  over  rough  boarding  with  furrings  and  wire  lath,  which  is  the  best  of  all. 

A  small  church  plastered  in  this  way  on  wood  lath  fourteen  years  ago  is  in  perfect 
condition  to-day,  and  various  houses  built  during  the  last  ten  years  have  proved  per- 
fectly satisfactory.  I  have  not  as  yet,  however,  found  any  method  of  building  true 
half-timbered  work  and  making  it  thoroughly  tight  without  making  a  wall  that  was 
practically  as  expensive  as  a  brick  wall. 

354.  External  Stucco. — External  plastering  of  buildings  was  at 
one  time  greatly  in  vogue  in  European  countries,  and  there  are  many 
examples  of  "  stucco  "-covered  buildings  in  the  older  portions  of  this 
country.  Formerly  lime  and  sand  were  used  for  the  purpose,  but  this 
material  is  not  very  durable.  If  it  is  desired  to  plaster  a  brick  build- 
ing to  imitate  stone  ashlar,  Portland  cement  is  the  only  material  that 
should  be  used.  It  should  be  mixed  with  clean  sharp  sand,  not  too 
fine,  in  the  proportion  of  3  parts  sand  to  i  of  cement.  The  wall  to 
be  covered  should  itself  be  dry,  but  the  surface  should  be  well  wet 
down  with  a  hose  to  prevent  it  from  absorbing  at  once  all  the  water 
in  the  cement ;  it  should  also  be  sufficiently  rough  to  form  a  good  key 
for  the  cement.  Screeds  may  be  formed  on  the  surface,  and  the 
cement  should  be  filled  out  the  full  thickness  in  one  coat  and  of  uni- 
foim  substance  throughout.  When  cement  is  put  on  in  two  or  three 
coats,  whether  for  exterior  or  interior  work,  the  coats  already  applied 


LATHING  AND  PLASTERING.  347 

should  on  no  account  be  allowed  to  dry  before  the  succeeding  layers  are 
added,  otherwise  they  are  quite  sure  to  separate. 

The  manufacturers  of  Acme  cement  plaster  claim  that  where  brick 
buildings  are  to  be  plastered  with  cement  on  the  outside,  that  their 
plaster  is  superior  to  Portland  cement  for  the  first  coat,  as  it  adheres 
more  firmly  to  the  brick,  and  will  hold  the  Portland  cement  and  the 
base  upon  which  it  is  spread  together. 

The  cement  may  be  marked  with  lines  to  represent  stone  ashlar 
before  it  becomes  hard.  If  it  is  desired  to  color  the  cement,  mineral 
pigments  must  be  used,  such  as  Venetian  red  or  the  ochres.  The 
natural  color  of  the  cement  may  be  lightened  by  the  addition  of  a 
very  little  lime. 

STAFF.* 

355.  Staff,  a  material  used  for  the  exterior  covering  of  all  the 
buildings  of  the  World's  Columbian  Exposition  at  Chicago,  may  be 
considered  as  almost  a  new  material  in  this  country,  although  it  has 
been  in  extensive  use  in  Europe  for  many  years.  A  large  part  of  all 
exterior  decoration  of  buildings,  both  public  and  private,  in  the  pro- 
vincial cities  of  Germany,  whether  ornament,  columns  or  statuary, 
is  made  of  staff,  and  in  instances  a  period  of  fifty  years  of  existence 
will  testify  to  its  enduring  qualities.  Staff  was  first  used  extensively 
in  the  construction  of  buildings  at  the  Paris  Exposition  of  1878,  and 
it  was  also  adopted  in  work  on  the  much  grander  buildings  of  the  ex- 
position of  1889.  The  methods  of  application  at  these  expositions 
were,  however,  widely  different  from  and  much  more  expensive  than 
those  employed  at  the  Columbian  Exposition. 

The  staff  for  the  World's  Fair  buildings  was  made  on  the  grounds 
at  Jackson  Park  in  the  following  manner  : 

The  ingredients  were  simply  plaster  of  Paris,  or  Michigan  plaster,  water  and  hemp 
fibre.  Hemp  was  used  to  bind  together  and  add  strength  to  the  cast,  and  the  New 
Zealand  fibre  was  preferred,  as  both  the  American  and  Russian  fibres  were  found  too 
•stiff.  The  first  step  in  making  staff  ornaments  is  the  creation  of  a  clay  model.  The 
model  is  heavily  coated  with  shellac,  and  a  layer  of  clay  separated  from  the  model 
by  paper  is  put  on  its  face  and  sides.  This  layer  of  clay  is  oiled  or  greased  and  a 
heavy  coating  of  plaster  and  hemp  is  put  over  it.  The  thickness  of  this  coating  is 
dependent  upon  the  size  of  the  model ;  sometimes  it  is  5  or  6  inches  thick  and  con- 
tains heavy  battens  of  wood  to  strengthen  it.  In  less  than  twenty-four  hours  this 
coating  is  hard  and  is  taken  off  the  clay  covering  the  model.  The  coating  thus 
removed  is  called  the  box.  Next  the  clay  is  removed  from  the  model  and  the  model 


*  The  following  description  of  this  material  is  taken  from  an  article  by  E.  Phillipson,  pub- 
lished in  the  Engineering  Record  of  June  4,  1892.  Mr.  Phillipson  had  charge  of  this  portion  of 
•the  work  on  the  World's  Fair  buildings. 


348  BUILDING  CONSTRUCTION. 

i 

is  thoroughly  oiled.  The  box  is  oiled  and  put  over  the  model,  leaving  the  space 
between  model  and  box  formerly  taken  up  by  the  clay  coating  a  free  space.  Holes 
have  previously  been  made  in  the  box,  and  upon  a  large  centre  hole  (sometimes  two  or 
three  in  large  pieces)  a  plaster  funnel  is  placed.  Molten  gelatine  is  poured  through 
these  funnels,  which  fills  every  space,  air  being  allowed  to  escape  through  small  holes 
in  the  box.  In  from  twelve  to  twenty-four  hours  the  box  is  again  removed,  placed 
hollow  side  up,  and  the  now  hardened  gelatine  is  removed  from  the  clay  model  and 
placed  in  the  box,  which  it  fits  perfectly.  The  clay  model  has  now  served  its  pur- 
pose, for  the  gelatine,  which  has  become  a  matrix  of  the  cast  desired,  is  used  in  the 
further  stages  of  the  work.  In  case  of  large  moulds  the  gelatine  matrix  is  sometimes 
cut  into  as  many  as  eight  pieces.  All  these,  of  course,  join  perfectly  in  the  box  and 
are  cast  from  as  if  from  a  single  matrix.  The  gelatine  mould  is  washed  a  number  of 
times  with  a  strong  solution  of  water  and  alum,  and  after  oiling  is  ready  for  the  oper- 
ation of  casting. 

The  plaster  for  the  staff  is  thoroughly  stirred  in  water,  and  the  hemp,  cut  into 
lengths  of  6  to  8  inches,  is  bunched  loosely,  saturated  with  the  plaster  and  put  in  the 
moulds  in  a  layer  of  about  I  inch  in  thickness.  Succeeding  handfuls  of  hemp  are 
thoroughly  interwoven  with  the  preceding,  the  hemp  being  expected  to  fill  in  all  the 
corners  of  the  cast.  When  the  mould  is  filled  the  back  is  smoothed  over  by  hand, 
and  later  the  cast  is  removed  from  the  mould.  The  time  consumed  from  starting  a 
cast  to  removing  it  from  the  mould,  is  for  a  cast  5'x2'6"  in  size,  about  twenty-five 
minutes.  After  the  removal  of  the  cast  care  must  be  exercised  in  either  standing  it 
up  or  laying  it  down  that  it  shall  not  collapse  or  lose  its  form  by  warping.  During 
the  summer  months  a  cast  of  the  dimensions  given  will  dry  thoroughly  in  about 
thirty-six  hours  and  is  then  ready  for  application.  In  the  winter  months  there  is 
danger  of  casts  freezing  before  they  are  dry,  and  in  that  event  they  are  apt  to  go  to 
pieces  when  warm  weather  comes.  A  good  workman  can  make  as  many  as  seventy- 
five  casts  in  one  mould,  and  then  the  gelatine  is  remelted  and  a  new  mould  made  of 
it,  the  box  being  good  for  use  for  an  indefinite  length  of  time.  In  making  pilasters 
or  mouldings,  etc.,  not  ornamented  or  under-cut,  plaster  and  wood  moulds  are  often 
used,  the 'latter  material  being  especially  preferred,  owing  to  its  durability. 

"Applied  to  a  frame  building,  staff  is  simply  nailed  on  to  the  rough 
construction,  and  a  cheap  brick  wall  covered  with  it  can,  at  a  com- 
paratively small  expense,  be  made  to  assume  a  classic  appearance 
In  building  a  brick  house  with  the  employment  of  staff  in  view,  it  is 
advisable  to  insert  wooden  furring  strips  in  the  brick,  as  these  sim- 
plify the  labor  of  putting  it  on.  For  cornice  work  it  is  claimed  that 
a  strength  and  boldness  of  design  are  possible  with  staff  which  cannot 
be  realized  with  other  materials. 

"At  the  Paris  Exposition  the  buildings  were  constructed  almost 
entirely  of  iron,  and  nearly  all  the  staff  was  cast  in  panels,  which 
were  set  in  iron  frames.  While  this  method  was  considered  excellent 
both  in  finished  effect  and  in  durability,  it  was  far  too  expensive  and 
tedious  to  be  employed  in  covering  the  much  more  extensive  struc- 
tures to  be  built  for  the  World's  Columbian  Exposition  Accord- 


LATHING  AND  PLASTERING.  349 

ingly,  after  many  weeks  of  study,  the  construction  department  decided 
to  construct  the  buildings  of  wood  and  to  nail  the  staff  directly  to  the 
furring. 

"The  name  '  staff'  properly  applies  to  material  that  is  cast  in  moulds,  and  not  to 
ordinary  plaster  or  cements  that  are  put  on  with  a  plasterer's  trowel.  Work  with  such 
materials  is  subject  to  well-understood  limitations  by  the  temperature  and  weather, 
but  atmospheric  influences  have  practically  no  effect  upon  staff.  This  has  been 
demonstrated  by  the  acres  of  staff  that  has  been  standing  all  winter  outside  the  various 
casting  shops  in  Jackson  Park.  No  attempt  has  been  made  to  keep  off  the  rain, 
snow  or  frost.  Several  pieces  of  it  have  been  submerged  for  over  a  month  at  a  time, 
allowed  to  freeze  and  thaw,  and  freeze  again  with  the  water,  and  when  taken  out 
they  were  found  to  be  perfectly  intact." 

While  this  material  admirably  answered  its  purpose  on  the  Fair 
buildings,  it  became  considerably  deteriorated,  and  evidently  would 
not  answer  in  such  a  climate  for  permanent  buildings  unless  kept  well 
painted.  In  fact,  it  appears  to  be  generally  conceded  that  Portland 
cement  is  about  the  only  material  that  will  endure  permanently  under 
the  trying  conditions  of  our  northern  climate.  In  warmer  and  dryer 
climates  compositions  of  plaster  are  largely  used  on  the  exterior  of 
buildings,  and  in  many  instances  they  have  lasted  for  centuries. 

The  cost  of  ''''staff"  as  used  on  the  World's  Fair  buildings,  varied 
from  $2  to  $2.25  per  square  yard.  Ordinary  cement  mortar  applied 
directly  to  the  walls  cost  about  thirty  cents  per  yard. 

356.  Whitewashing.— Although  not  properly  belonging  to  the 
plasterer's  trade,  this  work  is  often  included  in  the  plasterer's  specifi- 
cations. 

Common  whitewash  is  made  by  simply  slaking  fresh  lime  in  water. 
It  is  better  to  use  boiling  water  for  slaking.  The  addition  of  2 
pounds  of  sulphate  of  zinc  and  i  of  common  salt  for  every  half 
bushel  of  lime  will  cause  the  wash  to  harden  and  prevent  its  crack- 
ing. One  pint  of  linseed  oil,  added  to  a  gallon  of  whitewash  imme- 
diately after  slaking,  will  add  to  its  durability,  particularly  for  outside 
work.  Yellow  ochre,  lampblack,  Indian  red  or  raw  umber  may  be 
used  for  coloring  matter  if  desired. 

Whitewash  not  only  prevents  the  decay  of  wood,  but  conduces 
greatly  to  the  healthiness  of  all  buildings,  whether  of  wood  or  stone. 
It  does  not  adhere  well,  however,  to  very  smooth  or  non-porous  sur- 
faces. Two  coats  of  whitewash  are  required  on  new  work  to  make 
a  good  job. 


35° 


BUILDING  CONSTRUCTION. 


LATHING    AND   PLASTERING    IN    FIREPROOF 
CONSTRUCTION. 

357.  Wherever  lathing  is  required  in  buildings  that  are  intended 
to  be  thoroughly  fireproof,  only  stiffened  wire  or  expanded  metal  lath 

should  be  used.  If  one  of  the  hard 
plasters  are  to  be  used,  close-warp 
(2^x5  mesh)  should  be  specified, 
and  the  lathing  should  be  either 
painted  or  galvanized.  (See  Sec- 
tion 333.) 

In  build:ngs  having  hollow  tile 
floor  construction  but  very  little,  if 
any,  lathing  is  used,  as  all  the 
walls,  ceilings  and  partitions  are  of 

tile,  on  which  the  plastering  is  directly  applied.  For  such  buildings 
either  machine-made  lime  mortar  (such  as  is  described  in  Section 
340)  or  one  of  the  hard  plasters  should  be  used. 

Cornices,  false  beams,   etc.,  in  this  class   of  buildings  are  more 


Fig-  235- 


commonly  formed  by  furring  with  light  iron  and  covering  with  metal 
lath,  to  which  the  plastering  is  applied. 

The  method  of  forming  a  beam  and  cornice  in  this  way  is  shown 
by  Fig.  234.     The  general  profile  is  formed  by  bending  light  iron  by 


LATHING  AND  PLASTERING. 

hand  on  a  shaping  plate  to  the  desired  outline.  These  are  secured 
m  position  and  longitudinal  rods  fastened  to  their  angles,  after  which 
the  wire  lathing  is  applied. 

Fig.  235  shows  the  manner  of  furring  steel  and  iron  columns 
when  protected  by  wire  lath  and  plaster,  and  Fig.  2350  a  popular 
method  when  expanded  metal  is  used. 

Both  wire  lath  and  expanded  metal  have  been  very  extensively 
used  for  furring  elaborate  ceilings,  beams,  arches,  vaults,  etc.,  in 
public  buildings,  and  wherever  such  furring  has  been  removed  or 
examined  after  a  term  of  years,  it  has  always,  so  far  as  known,  been 
found  to  be  in  good  condition  and  free  from  rust. 

The  larger  portion  of  the  plaster  beams  and  ceilings,  domes,  etc., 
of  the  new  Congressional  Library  are  formed  with  expanded  metal 

on  iron  furrings,  also  the 
very  elaborate  ceiling  of  the 
dining  room  in  the  Chicago 
Athletic  Club  and  the  domes 
and  paneled  ceilings  of  the 
New  York  Clearing  House. 

In  the  main  corridor  of  the  Worthington  Building  in 
Chicago  an  elaborate  vaulted  mosaic  ceiling  is  supported 
by  a  background  of  hard  mortar  on  expanded  metal. 

The   extent   to  which  both  wire   lath   and  expanded 
metal  may  be  used  in  forming  a  base  for  mortar  and  cement 
appears  to  be  unlimited.     When  hollow  tiles  are  used  for 
Fig  236       fireproofing,  the  grounds  for  the  cornices  are  sometimes 
formed  of  terra  cotta,  as  shown  in  Fig.  236.     Such  grounds 
are  more  firm  to  carry  the  heavy  stucco,  and  the  plastering  is  not  as 
liable  to  be  broken  by  streams  of  water  in  case  of  fire.     They  are, 
therefore,  generally  preferred  to  metal  grounds,  and  are  used  almost 
entirely  in  the  U.   S.   Government   buildings  when  the   ceilings  are 
of   tile. 

The  various  pieces  forming  the  ground  should  be  bolted  to  the 
floor  construction  with  £-inch  T-head  bolts  spaced  not  over  12  inches 
apart  longitudinally,  and  at  least  two  bolts  to  each  piece. 

These  terra  cotta  grounds  are  usually  made  by  manufacturers  of 
flue  linings  and  pipes,  as  their  machinery  is  better  adapted  for  the 
purpose  than  that  used  for  making  fireprooof  tile. 

358.  Thin  Partitions  of  Metal  Lath  and  Studding.— As 
stated  in  Section  320,  partitions  only  2  inches  thick  are  now  quite 
extensively  used  in  office  buildings  and  hotels  to  economize  floor 


B  UILDING  CONS  TR  UC  TION. 


space.  Most  of  these  partitions  are  constructed  of  upright  studding 
of  f-inch  channel  bars  spaced  from  12  to  16  inches  on  centers  and 
fastened  securely  to  the  floor  and  ceiling.  On  one  side  of  this  stud- 
ding, metal  lathing,  preferably  of  stiffened  wire  cloth,  or  expanded 
metal,  is  stretched  and  securely  laced  to  the  studs.  The  partition  is 
then  plastered  on  both  sides  with  hard  plastering  and  finished  in  the 
usual  manner.  If  properly  executed  the  partition  will  be  stiff  enough 
to  answer  all  the  purposes  for  which  it  is  required,  and  is,  of  course, 
absolutely  fireproof.  Only  the  best  of  hard  wall  plasters  should  be 
used  for  such  partitions,  however,  as  the  stiffness  of  the  partition  de- 
pends very  much  upon  the  solidity  of  the  plastering;  hence  the  firmer 
and  harder  the  plastering  the  more  substantial  will  be  the  walls.  By 
using  2-inch  channels  and  lathing  both  sides 
a  very  stiff  partition  is  obtained,  but,  of 
course,  at  greater  expense. 

The  New  Jersey  Wire  Cloth  Co.  makes  a 
special  lathing  for  thin  partitions,  which 
has  a  J-inch  solid  rod  woven  in  at  intervals 
of  7!  inches.  The  lath  is  stretched  over 
the  studs  so  that  the  rods  cross  them  at 
right  angles.  The  lath,  after  being  tightly 
stretched,  is  laced  to  the  studs  at  every 
point  where  the  rods  cross  them. 

Expanded  metal  has  been  very  exten- 
sively used  in  the  construction  of  solid  par- 
titions. It  is  applied  the  same  way  as 
wire  lath  (by  soft  steel  wire),  except  that  be- 
ing in  flat  sheets  it  does  not  require  stretch- 
ing. Perforated  sheet  metal  lathing,  when  used,  is  generally  secured 
to  the  studding  by  trunk  nails  driven  through  the  lath  along  side  of 
the  stud  and  clinched  around  behind  it,  each  nail  being  driven  on 
the  opposite  side  of  the  stud  from  the  one  above  and  below. 

Provisions  for  Base  and  Picture  Mould. — If  wire  lath  of  the 
standard  mesh  is  used  some  provision  must  be  made  for  securing 
the  wooden  base  and  picture  mould. 

Fig.  237  shows  the  method  ordinarily  adopted  for  securing  the 
base.  For  securing  the  picture  mould,  strips  of  wood  may  be  laced 
to  the  lath  at  the  required  height  before  plastering. 

When  imbedded  in  the  plaster  these  strips  are  sufficiently  firm  to 
hold  the  picture  mould.  The  mould  should  be  put  up  with  screws, 
however,  and  not  with  nails. 


LATHING  AND  PLASTERING. 


351 


When  close-warp  lathing,  plastered  with  mortar,  is  used,  No.  14  or 
1 6  screws  will  engage  in  the  meshes  of  the  wirework,  and  all  wood- 
work can  be  fastened  directly 
to   the   partition   with  wood 
screws. 

Door  and  Window  Fram- 
ing.— The  usual  method  of 
framing  for  doors  and  win- 
dows has  been  to  set  up 
rough  wood  frames,  to  which 
the  adjoining  channel  is  se- 
curely  fastened  by  screws  or 
anchor  nails,  and  in  most 
cases  this  method  is  quite 
satisfactory. 

Fig.  237*2  shows  various 
styles  of  door  frames,  which 
differ  principally  in  the  char- 
acter of  the  finish.  Those 
sections  which  have  the 
widest  door  jambs  will  be 
found  the  stiffest.  Various 
modifications  of  these  details 
may  be  made  to  suit  the  judg- 
ment or  taste  of  the  archi- 
tect. 

Fig-  237^  shows  one 
method  of  constructing  the 
window  frames  in  corridor 
partitions.  The  style  of 
moulding  may  be  varied  to 
suit  the  taste  of  the  designer. 
In  warehouses  where  there 
is  to  be  heavy  trucking,  or 
where  iron  or  fireproof  doors 
are  to  be  used,  the  door 
frame  may  be  built  of  1^x1^- 
inch  angle  iron,  to  which  the 
first  stud  of  the  partition  should  be  riveted. 

In  extremely  large  doorways  and  on  freight  elevators  it  is  often  a 


3S2 


BUILDING  CONSTRUCTION, 


practice  to  make  the  frames  of  heavy  2-inch  channel  iron,  to  which 
are  hung  the  large  fireproof  doors. 

Partitions  of  thin  porous  tiling  were  described  in  Chapter  IX., 
Section  320. 

For  forms  of  specifications  for  solid  partitions  see  pages  389  and  390. 


Fig.  237*. 

PLASTERING  SUPERINTENDENCE. 

359.  This  consists  chiefly  in  seeing  that  the  work  is  performed  in 
accordance  with  the  specifications,  and  if  the  specifications  are  prop- 
erly written  much  of  the  vexation  of  superintendence  will  be  saved. 
The  points  which  the  superintendent  should  particularly  inspect  are 
the  following : 

Quality  of  Materials. — See  that  the  laths  are  of  the  kind  specified, 
and,  if  of  wood,  that  they  are  free  from  bark  and  dead  knots.  If  any 
such  laths  have  been  put  on  have  them  removed  and  clean,  sound 
laths  substituted.  See  that  the  lime  is  of  the  kind  specified  ;  if  it  is 
not  in  casks  it  will  be  well  to  require  the  plasterer  to  produce  the 
bills  for  the  lime  ;  also  that  the  lime  is  fresh  and  in  good  condition. 
Permit  no  lime  that  has  commenced  to  slake  to  be  used.  Inspect  the 
sand  to  see  that  it  is  free  from  earthy  matter,  and  that  it  is  properly 
screened.  Make  a  note  of  the  time  the  plasterer  commences  to  make 
the  mortar,  and  do  not  permit  him  to  use  it  until  it  is  at  least  seven 
days  old,  or  as  required  by  the  specifications. 

As  to  the  proportions  of  the  lime,  sand  and  hair,  not  much  can  be 
told  by  the  superintendent,  unless  he  has  the  quantities  measured  in 
his  presence,  which  will  involve  his  being  on  the  ground  most  of  the 
time.  Something,  however,  of  the  quality  of  the  mortar  and  of  the 
amount  of  hair  may  be  determined  by  trying  it  with  a  trowel.  The 
superintendent  should  endeavor  to  make  himself  familiar  with  the 
appearance  of  good  mortar.  See  that  the  hair  is  mixed  with  the 


LATHING  AND  PLASTERING. 


353 


mortar  at  the  stage  specified,  and  in  no  case  permit  it  to  be  mixed 
with  the  hot  lime. 

Lathing. — Before  the  workmen  commence  to  put  on  the  laths  the 
architect  or  superintendent  should  carefully  examine  all  grounds  and 
furring  to  see  that  they  are  in  the  right  place  and  are  plumb  and 
square.  If  the  chimney-breasts  are  furred,  as  is  the  custom  in  the 
Eastern  States,  they  should  be  tried  with  a  carpenter's  square  to  make 
sure  that  their  external  and  internal  angles  are  right  angles  ;  also  see 
that  all  angles  of  partitions  are  made  solid,  so  that  there  can  be  no 
lathing  through  the  angles. 

If  wooden  laths  are  used,  see  that  they  are  well  nailed  and  that 
they  are  not  placed  too  near  together  ;  |  of  an  inch  should  be  allowed 
on  ceilings  and  j  to  T5^  on  walls. 


_n 


j 


Fig.  238.  Fig.  239. 

See  that  the  end  joints  are  broken  at  least  every  18  inches  ;  if  the 
lather  will  do  so,  it  is  better  to  break  joint  in  every  course. 

See  that  the  laths  over  door  and  window  heads  extend  at  least  to 
the  next  stud  beyond  the  jamb  (as  in  Fig.  238),  so  as  to  prevent 
cracks  which  are  apt  to  appear  at  that  point ;  also  see  that  all  the 
laths  run  in  the  same  direction.  When  laths  run  in  different  direc- 
tions (as  in  Fig.  239)  cracks  are  sure  to  appear  where  the  change 
takes  place.  See  that  all  recesses  in  brick  walls  for  pipes,  etc.,  are 
covered  with  wire  or  expaaded  metal  lathing,  unless  they  are  to  be 
covered  with  boards. 

Also  see  that  all  wood  lintels  and  other  solid  timbers  that  are  not 
furred  are  covered  with  metal  lath.  The  juncture  of  wood  with 
brickwork  should  also  be  covered  with  metal  lathing.  If  any  kind 


354  BUILDING  CONSTRUCTION. 

of  metal  lathing  is  used  see  that  it  is  put  up  as  directed  by  the  man- 
ufacturers, and  that  all  wire  lathing  is  tightly  stretched  ;  see  that  the 
furrir.gs  are  properly  spaced  and  that  the  whole  is  well  secured. 

Before  the  plasterers  commence  work  the  superintendent  should 
see  that  the  building  is  closed  in  by  the  carpenter,  either  by  filling  the 
openings  with  boards,  old  sash  or  cloth.  Cotton  cloth  is  the  best 
material  for  the  purpose,  as  it  permits  of  some  circulation  of  air 
through  it. 

If  the  plastering  is  done  in  cold  or  freezing  weather  provision  must 
be  made  for  heating  the  building.  Ordinary  lime  plaster  is  com- 
pletely ruined  by  freezing  and  thawing,  and  plastering  that  has  once 
been  frozen  will  never  become  hard  and  solid. 

When  the  scratch  coat  is  partly  on  the  superintendent  should  try 
to  look  behind  the  laths  to  see  if  the  mortar  has  been  well  pushed 
through  between  them,  as  the  clinch,  or  key,  at  the  back  of  the  laths 
is  all  that  holds  the  plaster  in  place. 

See  that  the  first  coat  is  dry  before  the  second  is  put  on,  if  so  spec- 
ified ;  also  that  the  surface  of  the  brown  coat  is  brought  to  a  true 
plane,  the  angles  made  straight  and  square,  the  walls  plumb  and  the 
ceilings  level.  The  specifications  should  require  that  the  first  and 
second  coats  be  carried  to  the  floor,  behind  the  base  or  wainscoting. 

When  brick  walls  are  to  be  plastered  the  superintendent  should 
remember  that  a  much  firmer  job  of  plastering  will  be  obtained  if  the 
wall  is  well  wel  just  before  the  plastering  is  applied. 

If  the  first  and  second  coats  have  been  properly  put  on  the  finish 
coat  will  need  little  superintendence  beyond  seeing  that  proper 
materials  are  used  and  that  the  work  is  well  troweled,  if  hard  finish. 

If  any  of  the  improved  plasters  described  in  Sections  344-5  are 
used,  the  superintendent  should  see  that  the  instructions  furnished  by 
the  manufacturers  are  strictly  followed,  particularly  as  to  the  wetting 
of  the  laths  and  the  proportion  of  sand  used  ;  he  should  also  see  that 
no  mortar  that  has  commenced  to  set  is  remixed.  When  machine- 
made  lime  mortar,  or  any  of  the  hard  plasters  that  are  sold  already 
mixed  with  sand  and  fibre,  are  specified,  the  care  of  superintendence 
will  be  greatly  lessened.  If  improved  plasters  are  used  in  freezing 
weather  the  building  must  be  kept  above  the  freezing  point  until  the 
plaster  has  set. 

360.  Measuring  Plaster  Work. — Lathing  is  always  figured 
by  the  square  yard  and  is  generally  included  with  the  plastering, 
although  in  small  country  towns  the  carpenter  often  puts  on  the  laths. 

Plastering  on  plain  surfaces,  as  walls  and  ceilings,  is  always  meas- 


LATHING  AND  PLASTERING.  355 

ured  by  the  square  yard,  whether  it  be  one,  two  or  three-coat  work, 
or  lime  or  hard  plaster. 

Jn  regard  to  deducting  for  openings,  custom  varies  somewhat  in 
different  portions  of  the  country,  and  also  with  different  contractors. 
Son  e  plasterers  allow  one-half  the  area  of  openings  for  ordinary  doors 
and  windows,  while  others  make  no  allowance  for  openings  less  than 
7  square  yards. 

Returns  of  chimney  breasts,  pilasters  and  all  strips  less  than  12 
inches  in  width  should  be  measured  as  12  inches  wide.  Closets,  sof- 
fits of  stairs,  etc.,  are  generally  figured  at  a  higher  rate  than  plain 
walls  or  ceilings,  as  it  is  not  as  easy  to  get  at  them.  For  circular  or 
elliptical  work,  domes  or  groined  ceilings,  an  additional  price  is  also 
made.  If  the  plastering  cannot  be  done  from  tressels  an  additional 
charge  must  be  made  for  staging. 

Stucco  cornices  or  paneled  work  are  generally  measured  by  the  super- 
ficial foot,  measuring  on  the  profile  of  the  moulding.  When  less  than 
12  inches  in  girth  they  are  usually  rated  as  i  foot.  For  each  internal 
angle  i  lineal  foot  should  be  added,  and  for  external  angles,  2  feet. 

For  cornices  on  circular  or  elliptical  work  an  additional  price 
should  be  charged. 

Enriched  mouldings  are  generally  figured  by  the  lineal  foot,  the 
price  depending  upon  the  design  and  size  of  the  mould. 

Whenever  plastering  is  done  by  measurement  the  contract  should 
definitely  state  whether  or  not  openings  are  to  be  deducted,  and  a 
special  price  should  be  made  for  the  stucco  work,  based  on  the  full 
size  details. 

361.  Cost. — The  cost  of  lime  plastering  on  plain  surfaces,  includ- 
ing wooden  laths,  varies  from  twenty  to  thirty-five  cents  per  yard, 
according  to  the  times,  locality,  number  of  coats  and  quality  of  work. 
For  ordinary  three-coat  work,  with  white  finish,  twenty-five  cents  is 
probably  about  the  average  price  for  the  entire  country.  The  author 
has  known  very  good  work  to  be  done  at  twenty  cents  per  yard,  but 
there  was  no  profit  above  the  wages  of  the  men. 

Hard  plasters  cost  from  two  to  ten  cents  per  yard  more  than  lime 
plaster,  according  to  the  price  of  lime  and  freightage  on  the  hard 
plaster. 

Wire  or  metal  lathing  will  cost  from  twenty-five  to  forty  cents  per 
yard  more  than  if  wood  laths  were  used. 


356 


BUILDING  CONSTRUCTION. 


The  following  figures  give  the  average  price  for  various  kinds  of 
plastering  in  the  cities  of  New  York  and  St.  Louis  : 


DESCRIPTION  OF  WORK. 

AVERAGE  COST  IN  CENTS 
PER   SQUARE   YARD. 

Lime  Mcrtar  : 

New  York. 
30  to  35 
35  to  40 
70 

40 
40 

75 
75 
35 
24 

20 
24 

St.  Louis.* 

17  to  21 

20  to  25 

55 

22  tO  26 
60 

30 
25 
20 
20 

1  Three-coat  work  on  wood  laths  

1  Three-coat  work  on  stiffened  wire  lath*  

'Windsor  Cement  or  Adan.ant  on  brick  or  tile  

*Acme  or  Royal  cement  plaster  on  brick  or  tile  

*  Windsor  Cement  or  Adamant  on  stiffened  wire  lath3.. 
*Acme  or  Royal  cement  plaster  on  stiffened  wire  lath3. 
Cost  of  stiffened  wire  lath  on  wood  joist,  about  

Cost  of  expanded  metal  on  wood  joist  

Cost  of  Bostwick  lath  on  wood  joist  

Stucco  cornices,  less  than  12  inches  girth,  per  lineal  foot. 
When  more  than  12  inches  girth,  cost  per  square  foot.. 
Enrichments  cost  from  8  cents  up  per  lineal  foot  for 
each  member. 

1.  The  last  coat  to  be  white  finish. 

2.  Finished  with  lime  putty  and  plaster. 

3.  When  applied  on  wood  joist  or  furring  :  when  applied  over  metal  furrings  the  cost  is  about 
20  cents  per  yard  more. 

For  scratch  and  brown  coats  on  wood  laths,  with  f -inch  grounds, 
the  following  quantities  of  materials  should  be  required  to  100  square 
yards  :  1,400  to  1,500  laths,  10  pounds  of  three-penny  nails,  two  and 
one-half  casks  or  500  pounds  of  lime,  45  cubic  feet  or  fifteen  casks 
of  sand  and  four  bushels  of  hair. 

For  the  best  quality  of  white  coating  allow  90  pounds  of  lime,  50 
pounds  of  plaster  of  Paris  and  50  pounds  of  marble  dust. 

Colored  Sand  Finish. — In  most  instances  where  sand  finish  is 
used  on  interior  walls,  it  is  with  the  purpose  of  afterward  decorating 
in  water  color.  In  such  cases  the  finish  itself  may  be  colored  or 
stained  at  a  slightly  less  expense  than  with  water  color,  and  with  the 
advantage  that,  the  finish  being  stained  throughout  its  entire  mass, 
dents  and  scratches  will  not  show,  as  in  the  case  of  paint  or  kalso- 
mine.  For  coloring  sand  finish,  pulp  stains  of  the  best  quality 
should  be  used;  these  are  mixed  with  water  to  a  thick  cream  and 
then  thoroughly  mixed  with  the  finishing  mortar,  all  the  mortar  for 
one  room  being  mixed  at  one  time  to  get  it  uniform.  No  plaster  of 
Paris  should  be  used  in  colored  sand  finish,  as  it  will  streak  the  wall. 
Dry  colors,  also,  should  not  be  used,  as  thev  are  quite  sure  to  prove 
a  failure. 


:  These  prices  are  about  the  average  asked  in  the  West. 


CHAPTER  XII. 
CONCRETE  BUILDING  CONSTRUCTION. 


362.  Concrete  composed  of  broken  stone,  fragments  of  brick,  pot- 
tery, gravel  and  sand,  held  together  by  being  mixed  with  lime, 
cement,  asphaltum  or  other  binding  substances,  has  been  used  in 
construction  to  resist  compressive  stress  for  many  ages. 

The  Romans  used  it  more  extensively  than  any  other  material,  as 
the  great  masses  of  concrete,  once  the  foundations  of  large  temples, 
palaces  and  baths,  the  domes,  arches  and  vaultings  still  existing, 
together  with  the  core  or  interior  portions  of  nearly  all  the  ancient 
brick-faced  walls  found  in  Rome,  testify. 

In  the  forest  of  Fontainbleau  there  are  three  miles  of  continuous 
arches,  some  of  them  fifty  feet  high,  part  of  an  aqueduct  constructed 
.  of  concrete  and  formed  in  a  single  structure  without  joint  or  seam. 
A  Gothic  church  at  Vezinet,  near  Paris,  that  has  a  spire  130  feet  high, 
is  a  monolith  of  concrete.  The  lighthouse  at  Port  Said  is  another, 
1 80  feet  in  height. 

The  breakwaters  at  Port  Said,  Marseilles,  Dover  and  other  impor- 
tant ports,  are  formed  of  immense  blocks  of  concrete.  The  water 
pipes  and  aqueduct  at  Nice,  and  the  Paris  sewers,  are  also  notable 
modern  constructions  of  the  same  material. 

In  England  and  France  thousands  of  dwellings  have  been  built  of 
concrete,  in  place  of  brick  and  stone.  Many  of  these  are  now  stand- 
ing, after  more  than  half  a  century,  without  the  least  sign  of  decay. 
In  the  United  States  concrete  buildings  are  comparatively  few,  the 
only  notable  building  not  of  recent  date  being  the  large  barn  built 
at  Chappaqua,  N.  Y.,  by  Horace  Greeley,  more  than  thirty-five  years 
ago,  of  an  ordinary  kind  of  concrete;  this  building  has  stood  the  test 
of  exposure  and  is  as  good  to-day  as  when  built. 

The  architects,  engineers  and  capitalists  of  the  United  States  ap- 
pear to  have  been  the  most  timid  of  those  of  all  civilized  nations  to 
avail  themselves  of  the  value  of  concrete  as  a  building  material,  and 
it  is  only  since  the  year  1885  that  this  material  has  been  used  to  any 


358  BUILDING  CONSTRUCTION. 

extent  in  the  construction  of  buildings  except  for  the  purpose  of  foot- 
ings of  foundation  walls. 

Suitable  materials  for  making  concrete  are  available  in  almost 
every  locality,  and  in  most  places  solid  walls  of  concrete  are  cheaper 
and  more  enduring  than  those  of  brick  or  stone. 

A  concrete  building  needs  no  furring,  as  the  walls  are  proof  against 
dampness,  and  in  a  monolithic  construction  of  concrete  no  possible 
danger  to  the  structure  can  arise  from  fire  within  or  without  the 
building. 

While  concrete  in  any  form  is  not  likely  to  take  the  place  of  stone, 
brick  or  terra  cotta  for  architectural  work  to  any  great  extent,  yet  the 
author  believes  that  in  combination  with  iron  and  steel  it  is  destined 
to  fill  a  large  place  in  the  construction  of  buildings,  and  that  for 
warehouses,  large  stables,  wine  cellars,  etc.,  it  is  the  best  and  cheap- 
est material  for  producing  substantial  and  incombustible  work.  The 
author  also  believes  that  in  many  localities  cottages  and  larger  dwell- 
ings could  be  advantageously  built  of  concrete,  and  with  a  decided 
gain  in  durability  and  comfort. 

363.  Notable  Examples  of  Concrete  Buildings.— Perhaps 
the  best  known  of  all  concrete  buildings  in  the  United  States  are 
the  hotels  Ponce  de  Leon  and  Alcazar,  at  St.  Augustine,  Florida, 
Messrs.  Carrere  &  Hastings,  architects. 

These  buildings,  composed  entirely  of  concrete,  and  exhibiting  all 
the  strains  to  which  building  material  can  be  subjected,  present  an 
example  of  the  almost  limitless  use  to  which  concrete  can  be  put. 

For  the  construction  of  these  buildings  an  elevator  was  built  at  a 
central  point  of  the  operation,  to  the  full  height  of  the  intended  build- 
ing, and  as  the  walls  progressed,  story  upon  story,  runways  were 
made  to  each  floor,  and  the  concrete,  mixed  by  two  capacious  mixing 
machines  on  the  ground  level,  was  lifted  in  barrels  and  run  off  to  the 
place  of  deposit.  At  times  in  the  progress  of  the  work  400  pounds  of 
cement  were  used  in  the  concrete  in  a  single  day. 

The  time  transpiring  between  the  wetting  of  the  concrete  and  the 
final  running  in  place,  even  at  the  fifth  story,  was  not  more  than  ten 
minutes  at  any  time. 

The  concrete  was  composed  of  i  part  imported  Portland  cement,  2 
parts  sand  and  3  parts  coquina  (a  shell),  the  greater  part  passing 
through  a  £-inch  mesh. 

The  cost  of  the  concrete  in  place  was  about  $8  a  yard,  including 
arches,  columns,  etc.  In  plain  thick  walls  the  cost  was  often  much 
less. 


CONCRETE  BUILDING  CONSTRUCTION.        359 

In  the  basement  of  the  Alcazar  is  a  bathing  pool  100  feet  long,  60 
feet  wide  and  3  to  10  feet  deep,  all  made  of  concrete.  Rising  from 
this  pool  are  concrete  columns,  6  feet  square  at  the  base  ard  40  feet 
high.  These  columns  support  concrete  beams  of  25  feet  span,  hol- 
lowed out  in  arch  form,  which  support  the  glazed  roof  covering  the 
interior  court. 

364.  The  Leland  Stanford,  Jr.,  Museum,  at  Palo  Alta,  Cal- 
ifornia, a  very  large  and  costly  building,  is  also  constructed  entirely 
of  concrete.  This  building  was  built  on  the  Ransome  system— using 
twisted  iron  rods  imbedded  in  the  concrete  to  give  tensile  strength 
where  required. 

The  following  description  of  this  building,  written  by  the  architect, 
Mr.  Geo.  W.  Percy,  gives  some  idea  of  the  method  of  construction 
and  also  of  the  cost. 

This  building  was  designed  to  have  dressed  sandstone  for  the  external  walls, 
backed  up  with  brick,  and  to  have  brick  partitions  with  concrete  floors.  Owing  to 
the  great  cost  of  stonework,  it  was  decided  to  build  the  walls  of  cement  concrete, 


Fig.  240. 

colored  to  match  the  sandstone  used  in  the  other  university  buildings,  and  to  carry 
out  the  classic  design  first  adopted.  This  led  to  making  the  entire  structure  walls, 
partitions,  floors,  roof  and  dome  of  concrete,  making  it,  in  that  respect,  a  unique 
building. 

Having  some  knowledge  of  the  disadvantages  and  defects  natural  to  a  mono- 
lithic building,  such  as  result  from  the  shrinkage  and  the  expansion  and  contraction 
of  walls,  floor  and  roof,  several  new  experiments  were  tried  to  overcome  them,  with 
varying  results  of  success  and  failure.  It  was  thought  to  overcome  the  cracking  <>f 
walls  by  inserting  sheets  of  felting  through  the  walls,  following  the  lines  of  the 
joints  as  near  as  practicable  on  each  side  of  the  windows.  The  lapping  bond  of  the 
concrete,  however,  proved  too  strong  to  allow  the  cracking  to  follow  these  joints; 
in  most  cases  the  weakest  points  were  found  at  the  openings,  and  small  crackr 
appear  from  window  head  to  sills  above. 


36o 


B  UILDING  CONS  TR  UCTION. 


Joints  were  formed  through  the  floors  about  15  feet  apart  and  in  most  cases  the 
cracking  has  followed  these  joints  and  been  confined  to  them.  To  prevent  the 
possibility  of  moisture  penetrating  through  the  walls,  and  also  to  render  them  less 
resonant,  hollow  spaces  5  inches  in  diameter  were  moulded  in  the  walls  within  2 
inches  of  the  inside  face,  and  with  about  2  inches  of  concrete  between  thenu 
These  are  successful  for  the  primary  object,  and  partially  so  for  the  secondary. 
The  roof  being  the  greatest  innovation,  and  the  first  attempt  known  to  the 

writer  of  forming  a  finished 
and  exposed  roof  entirely  in 
concrete,  required  the  great- 
est care  and  consideration. 
The  result  in  form  and  ap- 
pearance is  shewn  by  Fig. 
240,  A  and  B,  and  may  be 
described  as  follows:  The 
roof  is  supported  on  iron 
trusses  10  feet  on  centre, 
and  has  a  pitch  of  20  de- 
grees. The  horizontal  con- 
crete beams  rest  on  the  iron 
rafters,  and  with  the  half 
arches  form  the  horizontal 
lines  of  tiles  about  2  feet  6 
inches  wide,  with  the  joints 
lapping  2  inches  and  a  strip 
of  lead  inserted  as  shown. 
Vertical  joints  are  made 
through  the  concrete  over 
each  rafter  with  small  chan- 
nels on.  each  side.  These 
joints  and  channels  are  cov- 
ered with  the  covering  tiles 
shown  on  drawings,  and 
similar  rows  of  covering 
tiles  are  placed  2  leet  6 
inches  apart  over  the  entire 
roof,  thus  forming  a  perfect 
representation  of  flat  Gre_ 
cian  tile  or  marble  roof.  Notwithstanding  the  precautions  taken,  this  roof  pre- 
sented several  unexpected  defects.  The  most  serious  proved  to  be  in  the  Venetian 
red  used  for  coloring  matter  and  mixed  with  the  cement.  This  material  rendered 
the  covering  tiles  absolutely  worthless,  many  of  them  slacking  like  lumps  of  lime, 
and  all  were  condemned  and  re-made.  The  same  material  injured  the  general  sur- 
face of  the  roof,  rendering  it  porous  and  necessitating  painting.  The  roof  over  the 
central  pavilion  being  hidden  behind  parapets,  is  made  quite  flat  and  covered  with 
asphaltum  and  gravel  over  the  concrete.  This  roof,  with  its  low,  flat  dome,  is 
without  question  the  largest  horizontal  span  in  concrete  to  be  found  anywhere  on 
earth,  being  46  feet  by  56  feet,  the  flat  dome  having  all  its  ribs  and  rings  of  con- 


Fig.  241. 


CONCRETE  BUILDING  CONSTRUCTION.        361 

Crete,  with  the  panels  or  coffers  filled  with  i-inch  thick  glass  and  weighing  about 
80,000  pounds.* 

This  structure  covers  21,000  feet  and  contains  over  1,100,000 
cubic  feet  of  space.  It  required  about  260,000  cubic  feet  of  con- 
crete, and  was  completed  in  seven  months  from  the  commencement 
of  the  foundations. 

The  cost  of  the  building  per  cubic  foot,  including  marble  stairs 
and  wainscoting,  cast  iron  window  frames  and  sashes,  and  other  parts 
to  correspond,  was  about  eighteen  cents,  which  is  a  very  low  figure 
for  a  thoroughly  substantial  and  fireproof  building. 

Other  important  buildings  which  have  been  executed  in  concrete 
in  the  vicinity  of  San  Francisco  are  the  Girls'  Dormitory  at  the 
Stanford  University  (a  three-story  building  completed  in  ninety  days 
from  the  time  the  plans  were  ordered),  the  Science  and  Art  build- 
ing, Mills  College  ;  the  Torpedo  Station  on  Goat  Island,  80x250  feet, 
and  an  addition  to  the  Borax  Works  at  Alameda.  In  the  latter  the 
walls,  interior  columns  and  all  floors  are  of  concrete,  and  are  remark- 
able for  the  lightness  of  the  construction  and  great  strength. 

All  of  these  buildings  were  built  on  the  Ransome  system. 

365.  The  Alabama  Hotel,  Buffalo,  N.  Y.— The  only  large 
building  constructed  of  concrete  in  the  Eastern  States  in  recent 
years  that  the  author  is  acquainted  with  is  the  Alabama  House,  at 
Buffalo,  N.  Y.,  Mr.  Carlton  Strong,  architect.  This  building  is 
€0x180  feet  in  size  and  six  stories  high,  with  all  walls,  floors  and 
partitions  built  of  concrete. 

The  general  plan  of  the  wall  and  floor  construction  is  shown  by 
Fig.  242,  which  represents  a  partial  section  at  level  of  third  floor. 

The  whole  thickness  of  the  wall  is  24  inches  from  top  to  bottom, 
the  inner  portion  being  2  inches  thick  for  the  whole  height ;  the 
outer  portion  is  8  inches  thick  in  first  story,  and  diminishes  by  i  inch 
in  each  story. 

Vertical  twisted  rods  are  built  in  the  walls,  as  shown  in  the  figure, 
except  that  they  are  spaced  about  15  feet  apart  lengthways  of  the 
wall.  Opposite  these  vertical  rods  the  withes  are  3  inches  thick,  else- 
where i£  inches  thick.  In  each  withe  are  built  £  inch  twisted  rods, 
extending  across  the  wall,  and  placed  12  inches  apart  vertically.  At 
•each  floor  level  f-inch  horizontal  bars  are  imbedded  in  the  walls 

*  Fig.  241  shows  an  interior  view  of  this  dome  and  the  hallway  and  corridors  beneath.  All 
the  construction  shown  in  this  view  is  of  concrete.  In  the  first  story  the  walls  are  cased  with 
«narble  slabs,  above  they  are  finished  with  plaster. 


362 


B  UILDING  CONS  TR  UC  TION. 


as  shown.  These  twisted  steel  bars  unite  perfectly  with  the  concrete 
and  tie  the  walls  together  in  all  directions,  while  the  shape  of  the 
wall  gives  the  greatest  stability  with  the  least  amount  of  material.  If 
will  be  noticed  that  the  plan  of  this  wall  is  very  similar  to  that  of  the 
wall  shown  in  Fig.  155.  The  concrete  wall  h-as  this  advantage  over 
the  brick  wall,  that  moisture  does  not  pass  through  the  solid  con- 


Bar 


crete  withes,  while  there  is  a  possibility  of  its  doing  so  in  brick 
withes.  The  spaces  in  the  wall  are  stopped  at  each  floor  level, 
except  that  for  purposes  of  smoke  flues  or  ventilation  some  of  them 
are  more  or  less  continuous. 

The  floors  in  this  building  are  built  on  the  Ransome  system,  of 
concrete  with  twisted  rods.  Most  of  the  floors  are  of  the  paneled 
construction  shown  in  Fig.  188  A,  although  s^me  portions  are  flat,, 
and  of  the  type  shown  in  Fig.  188. 


CONCRETE  BUILDING  CONSTRUCTION.       363 

The  partitions  are  also  constructed  of  concrete,  with  twisted  rods, 
and,  being  monolithic,  add  greatly  to  the  stiffness  of  the  building. 

Most  of  the  concrete  used  in  the  construction  of  this  building  was 
made  in  the  proportion  of  i  part  Portland  cement  to  6  parts  aggre- 
gates. 

The  contractors  state  that  the  average  cost  of  the  wall  was  twenty- 
five  cents  per  square  foot  of  outside  surface. 

This  building  was  commenced  in  1894  and  completed  in  1896. 

366.  Details  of  Construction.— The  usual  method  of  build- 
ing concrete  walls,  piers,  arches,  etc.,  is  by  setting  up  uprights  of  4x4 
or  4x6  scantlings  at  each  side  of  the  proposed  wall  or  pier  and  secur- 
ing to  them  boards  or  moulds,  between  which  the  concrete  is  depos- 
ited and  rammed.  To  prevent  springing  the  standards  should  be 
bolted  together  through  the  wall.  For  the  moulding  boards,  dressed 
pine  boards  \\  inches  thick  are  recommended  ;  these  should  be 
brushed  with  a  hot  solution  of  soap  each  time  before  using.  After 
the  lower  portion  of  the  concrete  has  set  the  moulding  boards  may 
be  removed  and  used  above. 

Mr.  Ernest  Ransome,  who  has  had  much  experience  in  the  erec- 
tion of  concrete  buildings,  has  patented  a  movable  cribbing,  which 
consists  of  slotted  standards,  which,  being  placed  in  pairs,  one  on  each 
side  of  the  wall,  and  bolted  together,  hold  in  position  the  mould 
boards.  These  standards  may  be  raised  from  time  to  time  as  the 
work  progresses  without  interrupting  the  filling  in  of  the  concrete. 
In  connection  with  the  movable  cribbing  a  series  of  hoisting  buckets, 
with  a  traveling  crane,  is  provided  for  hoisting  the  concrete.  One 
man  stationed  upon  the  wall  receives  and  empties  the  buckets  of  con- 
crete as  they  are  hoisted  and  rams  the  concrete  into  place.  The 
crane  may  be  moved  around  the  wall  upon  the  upright  slotted 
standards,  so  that  no  scaffolding  whatever  is  required  about  the  wall. 
It  is  claimed  that  the  expense  of  working  this  apparatus  need  not 
exceed  a  cent  per  cubic  foot  of  concrete.  The  first  cost  is  also  small. 

When  mouldings  are  to  be  formed  on  the  wall  the  reverse  profile 
of  the  mould  is  stuck  in  wood  and  set  in  its  proper  place  on  the 
mould  boards. 

Buildings  of  concrete  may  be  erected  very  rapidly,  as  the  process 
of  depositing  the  concrete  goes  on  continuously  all  around  the  build- 
ing, and  there  is  no  stone  to  cut  or  set,  and  with  proper  foresight 
there  need  be  no  waiting  for  materials. 

Concrete  Beams  or  Lintels.—  Wherever  lintels  or  beams  occur  in  con- 
crete buildings  they  should  be  formed  of  concrete  and  twisted  rods 


364 


BUILDING  CONSTRUCTION. 


or  cables  in  the  manner  shown  in  Fig.  243.  A  beam  like  that  shown, 
22  inches  wide  and  2  feet  10  inches  high,  was  used  in  a  building  in 
San  Francisco,  where  it  carries  three  stories  of  brick  walls  and  wood 
floors,  with  a  clear  span  of  15  feet.  The  twisted  bars  were  i  inch 
square.  The  three  bars  near  the  top  were  placed  only  over  the  sup- 
porting posts  to  give  the  effect  of  a  continuous  girder. 

367.  Surface  Finish. — Most  of  the  concrete  buildings  con- 
structed previous  to  1885  were  finished  on  the  outside  with  plas- 
ter or  stucco  in  the  manner  described  for  plastering  brick 
walls,  Section  354.  This  finish  has  not  proved  very  satisfactory, 
and,  moreover,  added  considerably  to  the  cost  of  the  wall.  This 

unsatisfactory  surface  finish 
undoubtedly  has  had  much  to 
do  with  the  limited  use  of  con- 
crete for  wall  construction. 

It    has    been    demonstrated, 
however,  that  the  natural  face 
of   the   concrete  can,  at  slight 
expense,  be  finished  to  closely 
imitate  roughly  dressed  stone- 
work.    Such    imitation,    more- 
over, is  not,  as  in  most  cases,  a 
false  pretense  or  sham,  as  such 
surface  finish  is   as  natural  to 
concrete  as  to  stone — concrete 
being  in  fact  an  artificial  stone. 
The  usual  method  of  finish- 
ing   the    surface    of    concrete 
walls,   when    it    is    desired   to 
imitate  stonework,  is  by  form- 
ing imitation  joints  in  the  face  of  the  wall,  and  either  picking  or 
tooling  the  surface  of  the  blocks  thus  formed,  the  former  giving  the 
appearance  shown  on  the  face  of  the  wall,  Fig.  242. 

The  joints  are  formed  by  lightly  nailing  to  the  inside  face  of  the 
moulding  boards  cleats  or  strips,  moulded  or  beveled  to  give  the 
desired  form  to  the  recessed  joint.  After  nailing  on  the  strips  the 
inner  face  of  the  mould  or  cribbing  will  appear  something  like 
Fig.  244,  the  shape  and  size  of  the  blocks  varying  to  suit  the  char- 
acter of  the  work  and  the  divisions  of  the  wall. 

In  imitating  rough- dressed  work  the  mould  is  taken  from  the  con- 
crete while  it  is  yet  tender,  and  with  small  light  picks  the  face  of  the 


Fig.  243. 


CONCRETE  BUILDING  CONSTRUCTION.        365 

stone  is  picked  over  with  great  rapidity,  an  ordinary  workman 
finishing  about  1,000  superficial  feet  per  day.  (The  first  and  second 
stories  of  the  Alabama  House  are  finished  in  this  way.) 

For  imitations  of  finer-tooled  work  the  concrete  should  be  left  to 
harden  longer  before  being  spalled  or  cut,  and  the  work  should  be 
done  with  a  chisel. 

A  very  neat  effect  may  be  obtained  by  chiseling  a  margin  around 
the  blocks  to  imitate  tooled  work,  and  then  picking  the  centre,  as 
shown  in  Fig.  245. 

If  the  strips  are  properly  planed  and  beveled  the  recessed  joints  will  need  no 
"touching  up."  Most  natural  stones  (especially granite),  bricks  and  clinkers,  if 
crushed  sufficiently  fine,  make  excellent  material  for  this  face,  but  ordinary  cravel 
will  do. 


iinifiiiii'iiiiinilifii'fiitiiiiiiiiiiiiiiliiiiB  Jiiiiiini'iiiiiAtiiiAiiiiii 


niiiiiliiiiniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiinnniiiiiiniiiiii 


Fig.  245. 

Whatever  is  used,  let  it  be  uniform  in  color  and  of  an  even  grade.  When  a  very 
fine  and  close  imitation  of  a  natural  stone  is  required,  take  the  same  stone,  crush  it, 
and  mix  it  M'ith  cement,  colored  to  correspond. 

The  finer  the  stone  is  crushed  the  nearer  the  resemblance  will  be  upon  close 
inspection  ;  but  for  fine  work  it  is  generally  sufficient  to  reduce  the  stone  to  the 
size  of  buckshot  or  fine  gravel. 

Rough  effective  work,  excellent  in  appearance,  can  be  obtained  by  using  the 
ordinary  concrete  made  with  coarse  materials.  For  a  finer  grade  a  better  material 
should  be  used,  with  aggregates  of  coarse  sand,  very  small  gravel  or  finely-crushed 
stone.  This  fine  grade  need  not  extend  through  the  mass  of  the  concrete,  but  can  be 
applied  at  the  surface  only,  and  by  coloring  in  imitation  of  various  natural  stones, 
the  most  effective  and  pleasing  results  are  obtained. 

The  large  bridge  in  Golden  Gate  Park,  San  Francisco,  was  made  with  coarse 
concrete,  mixed  I  of  cement,  2  of  sand  and  6  of  quartzite  rock  taken  out  of  adjacent 
hills  and  simply  broken  by  hammers  without  screening,  and  notwithstanding  its 
coarseness  the  structure  has  frequently  been  mistaken  for  natural  stone  by  the 
public.* 

368.  Making"  the  Concrete. — Materials  and  Proportion. — ; 
Concrete  for  monolithic  construction  should  be  made  of  a  good 


'Mr.  E.  L.  Ransome. 


366  BUILDING  CONSTRUCTION. 

quality  of  Portland  cement,  mixed  with  clean,  sharp  sand  and  a  proper 
proportion  of  aggregates.  As  previously  stated,  almost  any  natural 
stone,  when  broken  up,  ordinary  gravel,  or  even  broken  bricks  or 
pottery,  may  be  used  for  the  aggregates.  Quartzite  rock  and  granite 
make  the  best  concrete,  but  the  other  materials  will  answer.  Shells 
were  used  for  the  aggregate  in  the  Hotel  Ponce  de  Leon. 

The  proportions  may  vary  from  i  to  4  to  i  to  8.  The  proportions 
used  in  the  buildings  mentioned  are  given  in  the  description. 

Mixing. — For  small  buildings  the  concrete  may  be  mixed  by  hand, 
as  described  in  Section  142,  but  if  very  much  concrete  is  required,  it 
will  be  found  much  more  economical  to  mix  it  by  a  regular  mixing 
machine. 

Concrete  can  also  be  much  more  thoroughly  mixed  in  a  machine 
properly  constructed  for  the  purpose  than  is  possible  by  hand,  and 
the  strength  of  the  concrete  is  increased  in  proportion. 

Relative  Strength  of  Mill  and  Hand-Mixed  Concrete. — The  opin- 
ions of  engineers  regarding  mill-mixed  concrete  vary  considerably. 
Some  claim  that  it  is  not  so  good  as  hand-mixed,  while  others  would 
not  think  of  using  hand-mixed  concrete  except  on  very  small  work. 
This  difference  in  opinion  is  undoubtedly  due  to  the  difference  in 
the  working  of  the  mills  used.  With  the  better  class  of  mills  there 
can  now  be  no  doubt  that  turning  the  concrete  many  times  greatly 
increases  its  strength. 

In  a  series  of  tests  with  one  mill  it  was  found  that  the  same  con- 
crete, which  when  hand-mixed  gave  a  crushing  strength  of  25  tons 
per  square  foot  when  one  month  old,  when  turned  in  the  mill  500 
times  gave  a  crushing  strength  of  over  90  tons  when  one  week  old. 

Another  series  of  tests  furnished  the  author  by  Mr.  E.  L.  Ransome 
gave  the  following  results: 
I  part  Portland  cement.  I  Rosendale,  12  limestone. ..      I,     2,     3,     4,       8  weeks. 

No.  I.   Mixed  by  hand  very  thoroughly 36,   —    36,    54,     68 

No.  2.  Mixed  in  mill  and  turned  500  times 54,   81,  90,  90,    117 

There  is  probably  no  doubt  that  in  this  country,  at  least,  sufficient 
attention  has  not  been  given  to  the  thorough  mixing  of  the  concrete, 
most  architects  and  engineers  placing  more  stress  upon  the  question 
of  tamping  than  upon  that  of  mixing,  whereas  the  latter  is  by  far  the 
more  important  of  the  two. 

Some  years  ago  Mr.  John  Grant,  the  engineer  of  the  Metropolitan 
Drainage  Canal  system  of  London,  demonstrated  that  the  advantage 
gained  by  tamping  over  the  untamped  concrete  did  not  exceed  40 
per  cent.  Within  the  past  five  years  Mr.  E.  L.  Ransome  has  dem- 


CONCRETE  BUILDING  CONSTRUCTION.        367 

onstrated  that  the  best  mill-mixed  concrete  and  the  best  hand-mixed 
concrete  vary  over  100  per  cent,  in  strength.  By  means  of  mill  mix- 
ing, therefore,  it  is  possible  to  obtain  a  better  and  stronger  concrete 
with  a  smaller  proportion  of  cement,  and  consequently  at  less  cost. 
'Inspection. —  Concrete  work  cf  all  kinds  requires  the  most  rigid 
inspection  (see  Section  85),  as  almost  everything  depends  upon  the 
quality  of  the  cement  and  proper  mixing.  Unless  thorough  confidence 
can  be  placed  in  the  honesty  of  the  contractor  to  use  the  proportion 
of  cement  specified,  it  will  be  necessary  to  keep  an  inspector  con- 
stantly on  the  ground  to  see  that  the  full  proportion  of  cement  is 


'^'1    A 

jv  v-:.:-^^  ;"•.  ft'v'v^;'^  v  pSSs 

& 

1 

^1 

if— 

0-'>v"^:'\|;f{' 
^11 

ELEVATION 


PLAN   alC-D. 


Fig    246. 


used.     The  quality  of  the  cement  furnished  should  also  be  tested 
from  time  to  time  as  the  work  progresses. 

369.  Expansion  and  Contraction. — Concrete  diminishes 
slightly  in  volume  in  setting  in  air,  and  in  monolithic  construction 
this  contraction  is  sufficient  to  produce  cracks  throughout  the  walls 
and  floors.  Some  method  should  always  be  employed,  therefore,  to 
allow  for  expansion  and  contraction  and  to  make  the  cracks  follow 
ialse  joints  in  the  work.  One  method  adopted  for  accomplishing  this 
result  in  walls  is  shown  by  Fig.  246.  Through  joints  are  formed  at 
intervals  by  means  of  an  iron  plate,  shown  at  P  and  on  the  plan. 
This  plate  is  pulled  up  as  the  wall  increases  in  height,  leaving  an 
open  joint  through  the  wall.  Wherever  these  joints  occur,  recesses 


368  BUILDING  CONSTRUCTION. 

are  left  in  every  alternate  course,  as  shown  at  A  A.  These  recesses 
are  afterward  filled  with  concrete  blocks,  formed  separately  and  set 
in  mortar  like  a  stone.  If  the  concrete  contracts  or  settles  the  break 
will  take  place  in  the  joints  thus  formed,  and  will  not  show  on  the 
face  of  the  wall. 

Window  sills  should  also  be  put  in  as  slip  sills,  so  that  any  settle- 
ment in  the  wall  will  not  crack  the  ends  of  the  sills.  If  the  wall  is 
jointed  on  the  surface,  as  shown  in  Figs.  242  or  245,  the  window 
heads  should  be  made  in  the  form  of  a  flat  arch  and  a  recess  left  for 
the  key,  which  should  be  put  in  afterward.  It  is  also  advisable  to 
have  a  through  joint  over  the  centres  of  all  windows. 

When  first  attempting  a  concrete  building,  the  architect  will  do 
well  to  consult  with  some  person  who  has  had  experience  with  con- 
crete building  as  to  the  best  arrangement  of  overcoming  the  effects 
of  contraction  and  expansion. 

Concrete  walls,  with  iron  ties  imbedded,  when  cracked,  however, 
are  not  in  the  bad  condition  of  stone  or  brick  walls  without  such 
bond,  as  the  iron  ties  may  be  depended  upon  to  prevent  spreading  or 
falling. 

370.  Fireproof  Vaults.— One  of  the  rooms  in  the  Leland  Stan- 
ford, Jr.,  Museum  was  designed  to  be  the  receptacle  of  many  valu- 
ables, and  to  render  it  burglar-proof,  the  floor,  walls  and  ceiling  had 
copper  wires  imbedded  in  the  concrete  not  over  3  inches  apart,  form- 
ing a  continuous  circuit,  and  designed  to  strike  an  alarm  bell  at  the 
University  if  any  wire  should  be  cut. 

This  device  has  also  been  in  use  in  the  U.  S.  Sub-Treasury  in  San 
Francisco  for  several  years ;  it  would  seem  to  be  very  effective  for 
prison  walls  and  cells. 

Even  without  this  electrical  safeguard,  concrete  vaults  may  be 
made  so  as  to  resist  the  attempt  of  burglars  for  a  long  time  and  at  a 
comparatively  slight  expense. 

Iron  rods,  old  iron  or  steel,  may  be  imbedded  in  the  walls,  floor 
and  ceiling  to  as  great  an  extent  as  may  be  deemed  necessary  ;  these, 
being  firmly  held  by  the  concrete,  will  be  very  difficult  to  cut  or 
remove.  Such  vaults  would  also  be  thoroughly  fireproof,  and,  if 
made  of  sufficient  thickness,  would  keep  their  contents  unharmed, 
even  should  the  building  be  completely  destroyed. 

"  On  one  occasion,  while  building  a  concrete  bank  vault  in  an 
interior  town,  several  tons  of  worn-out  plowshares  were  placed  in 
the  concrete  in  such  positions  as  would  be  most  likely  to  discourage 
burglars  in  attempting  to  cut  through  the  wall."  * 

*  Mr.  G.  W.  Percy,  in  Building. 


CONCRETE  BUILDING  CONSTRUCTION.        369 

371.  Sidewalk  Construction.— For  constructing  sidewalks 
over  areas  or  vaults,  concrete  may,  in  most  localities,  be  used  to  bet- 
ter advantage  as  regards  quality  and  economy  than  any  other  mate- 
rial or  form  of  construction,  as  the  concrete  not  only  furnishes  the 
necessary  strength,  but  also  the  finished  walk. 

Fig.  247  shows  a  section  of  monolithic  sidewalk  construction 
designed  to  obtain  the  maximum  benefit  from  the  glass  discs  built  in 
the  walk.  No  iron  whatever  is  used  in  the  construction  of  this  walk, 
except  for  the  twisted  bars  and  the  columns  supporting  the  beam  A. 
As  such  sidewalks  are  usually  constructed  a  beam  is  placed  under 
the  wall  to  support  the  inner  edge  of  the  walk.  This  beam  naturally 
obstructs  much  of  the  light  disperc  J  by  the  glass  discs.  In  the  con- 
struction shown  the  weight  of  the  sidewalk  is  supported  entirely  by 


SECTION  thro1  SIDEWALK 


t±i 


SECTION  ONUNEX-Y. 

Fig.  247. 

the  area  wall,  the  beam  A  and  the  columns  beneath.  The  beams  B 
are  made  to  act  as  cantilevers,  £-inch  twisted  bars  being  imbedded  in 
the  top  of  the  beams  and  crossways  between  the  lights.  The  bars  in 
the  top  of  beams  B  are  carried  5  or  6  feet  beyond  the  beam  A,  and 
the  beams  B  are  placed  opposite  those  marked  C.  The  beams  A 
and  C  have  f  or  i  inch  bars  imbedded  near  the  bottom  to  furnish 
the  tensile  strength. 

If  necessary,  the  columns  may  also  be  dispensed  with  by  putting 
trimmer  beams  opposite  the  piers  to  support  the  beam  A. 

Other  Uses  for  Concrete  Construction. — There  are  vari- 
ous other  uses  which  might  be  advantageously  made  of  concrete  con- 
struction, such  as  foundation  and  area  walls,  retaining  walls  and  area, 
steps. 

When  the  foundation  walls  start  from  different  levels  Portland 
cement  concrete  may  be  used  with  especial  advantage,  as  it  is  sub- 
ject to  but  very  little,  if  any,  settlement  or  compression,  and  conse- 
quently if  the  settlement  of  the  ground  is  uniform  no  cracks  will  ap- 
pear in  the  walls. 


BUILDING  CONSTRUCTION. 

It  is  also  claimed  that  concrete  gives  a  drier  basement  than  stone 
or  brick,  and  in  many  localities  it  should  be  cheaper.  The  walls 
should  be  built  in  the  manner  described  in  Section  366,  using  plain 
boards  for  the  moulds. 

For  retaining  walls  concrete-iron  construction  would  appear  to  be 
eminently  adapted,  as  there  is  always  a  tendency  in  such  walls  for 
the  joints  to  open  at  the  back,  or  for  the  upper  part  to  slide  on  the 
lower.  Both  of  these  tendencies  are  readily  overcome  by  using  Port- 
land cement  concrete  and  twisted  iron,  and  the  wall  need  only  be 
made  of  such  thickness  that  it  cannot  be  overturned  bodily. 

Concrete  is  also  well  adapted,  in  many  localities,  for  steps  to  areas, 
or  in  terraced  grounds  to  ascend  from  one  level  to  another.  Such 
steps  are  generally  more  exposed  to  moisture  and  dampness,  and  dis- 
integrate more  quickly,  if  of  stone,  than  in  almost  any  other  situa- 

tion.  With  concrete  steps  the 
damPness  simP1y  increases  their 
strength  and  hardness. 

Where  the  ground  is  firm  con- 
crete steps  may  be  built  by  shap- 
ing the  ground,  then  setting  up  a 
form  for  the  risers,  and  filling  in 
the  concrete  between  the  form  and 
Flg' 248>  the  ground,  the  treads  being 

smoothed  off  with  a  trowel.  By  placing  f-inch  twisted  bars  in  the 
angles,  as  shown  in  Fig.  248,  these  steps  may  be  made  fully  as  strong 
as  if  built  of  stone,  and  more  durable. 

The  thickness  of  the  concrete  should  be  from  2  to  3  inches.  On 
doubtful  ground  or  any  ground  that  is  subject  to  frost,  ^-inch  twisted 
bars  should  be  bent  to  the  shape  of  the  steps  and  built  in  the  con- 
ciete,  as  shown  in  the  figure,  to  prevent  the  treads  and  risers 
being  broken  by  settlement  or  heaving  of  the  ground.  These  smaller 
bars  may  be  placed  from  i  to  4  feet  apart,  according  to  the  nature 
of  the  soil. 

Where  the  ground  is  not  sufficiently  firm  to  sustain  the  concrete 
without  assistance,  a  thin  sheet  of  iron  may  be  set  up  to  hold  the 
back  of  the  riser,  as  shown  by  the  heavy  line,  and  after  the  concrete 
riser  has  been  formed  the  iron  can  be  withdrawn,  the  earth  tamped 
slightly,  and  the  same  iron  used  for  the  next  step,  and  so  on,  step  by 
step. 

Test  of  Concrete  Slabs  Built  oo  the  Ransome  Sys- 
tem.— The  following  tests  of  the  transrerse  and  shearing  strength 


CONCRETE  BUILDING  CONSTRUCTION.      3696 

a-id  the  resistance  to  impact  of  a  concrete  slab  4  inches  thick  were 
made  by  Prof.  Miller,  Chief  of  the  Engineering  Laboratory  of  the 
Massachusetts  Institute  of  Technology,  early  in  1896: 

The  slab  was  5  feet  wide,  14  feet  long  and  4  inches  thick,  with 
f -inch  twisted  steel  bars  6  inches  on  centres  imbedded  near  the  bot- 
tom. The  concrete  was  made  of  i  part  Alsen  cement,  i  part  sand 
and  6  parts  broken  stone  (2  parts  passing  through  a  £-inch  ring  and 
4  parts  through  a  ^-inch  ring). 

The  slab  was  laid  over  the  tops  of  four  steel  I-beams,  spaced  4 
feet  8  inches  apart  on  centres,  thus  making  a  continuous  beam  of 
three  equal  spans.  Over  the  supports  ^-inch  twisted  bars,  3  feet 
long,  were  imbedded  in  the  top  of  the  concrete. 

The  first  section  was  tested  by  building  a  brick  pier  over  its  entire 
area  until  a  load  of  724  pounds  per  square  foot  was  attained,  when 
the  deflection  was  -j5^  inch,  without  cracking.  On  the  middle  span  a 
spruc6  beam,  8x12  inches  and  8  feet  4  inches  long,  weighing  164^ 
pounds,  was  dropped  five  times  from  a  height  of  7  feet  10  inches, 
twice  striking  in  the  same  spot,  without  doing  any  damage. 

By  means  of  screw  jacks  a  pressure  of  6,200  pounds  was  applied 
on  an  area  of  about  3x9  inches  between  two  twisted  bars  without 
breaking;  on  increasing  the  pressure  the  concrete  cracked  and  failed. 
Finally  a  steel  beam  was  laid  across  the  centre  of  the  middle  span 
and  a  load  of  20,700  pounds  put  on  by  a  jack  screw  before  the  con- 
crete cracked,  the  deflection  reaching  i^j  inch. 

The  makers  of  the  slab  claim  that  by  giving  more  twist  to  the  bars 
and  by  using  a  greater  quantity  of  sand  even  a  much  higher  resist- 
ance can  be  attained. 


CHAPTER  XIII. 
SPECIFICATIONS. 


372.  The  specifications  for  any  particular  piece  of  work  should 
be  considered  as  of  equal  importance  with  the  drawings.  The  archi- 
tect should  not  expect  the  contractor  to  do  anything  not  provided 
for  by  the  plans  and  specifications  without  extra  compensation,  nor 
to  do  the  work  better  than  the  specifications  call  for.  He  must 
therefore  be  sure  that  everything  which  he  wishes  done  is  clearly 
indicated  either  by  the  plans  or  specifications,  and  that  no  loopholes 
are  allowed  for  poor  workmanship  or  inferior  materials.  The  por- 
tions of  the  work  to  be  done  by  each  contractor  should  also  be  clearly 
stated,  so  that  there  can  be  no  misunderstanding  as  to  who  is  to  do 
certain  portions  of  the  work.  It  very  often  happens  that  some  minor 
details,  such  as  closing  up  the  windows,  protecting  stonework,  etc., 
are  not  properly  specified,  and  the  contractors  dispute,  much  to  the 
annoyance  of  the  architect,  as  to  who  shall  do  that  part  of  the  work. 
Such  annoyances  are  largely  avoided  when  the  entire  contract  for  the 
erection  and  completion  of  the  building  is  given  to  one  person  or 
firm,  but  even  then  it  is  better  to  have  the  duties  of  the  sub-contract- 
ors clearly  defined. 

As  a  rule,  the  form,  dimensions  and  quantity  of  all  materials 
should  be  fully  indicated  on  the  drawings,  so  that  only  the  kind  and 
quality  of  the  materials  and  the  manner  of  doing  the  work  need  be 
given  in  the  specifications.  General  clauses  should  be  avoided  as  far 
as  possible,  as  they 'only  cumber  the  specifications  and  tend  to 
obscure  the  really  important  portions. 

The  following  forms  of  specifications  for  various  kinds  of  mason 
work  are  given  merely  as  a  guide  or  reminder  to  architects,  and  not 
always  to  be  copied  literally.  Figures  or  words  enclosed  in  (  )  may 
be  changed  to  suit  special  or  local  conditions. 

Every  specification  should  be  prepared  with  special  reference  to 
the  particular  building  for  which  it  is  intended. 

The  use  of  standard  specifications  is  not  recommended,  as  when 
such  specifications  are  used  the  architect  is  more  apt  to  overlook 
important  points,  and  the  use  of  such  forms,  moreover,  tends  to  a 
lack  of  progressiveness  and  a  study  of  the  best  construction  to  suit 
the  varying  circumstances  of  different  buildings. 


SPECIFIC  A  TIONS.  3  7  x 

The  author  would  recommend  to  the  young  architect  that  before 
commencing  to  write  or  dictate  his  specifications  he  make  a  skeleton, 
consisting  of  headings  of  the  different  items  to  be  specified,  carefully 
looking  over  the  plans  and  revising  the  skeleton  until  everything 
seems  to  be  covered  and  the  headings  arranged  in  their  proper 
sequence.  The  specifications  can  then  be  filled  out  in  the  manner 
herein  indicated. 

GENERAL  CONDITIONS. 

373-  Every  specification  should  be  preceded  by  the  general  con- 
ditions governing  all  contractors.  These  may  advantageously  be 
printed  on  a  separate  sheet  and  used  as  a  cover  to  the  written  speci- 
fication, and  should  not  be  repeated  in  the  latter. 

The  general  conditions  used  by  different  architects  vary  more  or 
less,  according  to  the  experience  of  the  architect. 

The  following  form  has  been  used  by  the  author  for  a  number  ot 
years  with  satisfactory  results  : 

General  Conditions  :— The  contractor  is  to  give  his  personal  superintendence, 
and  direction  to  the  work,  keeping,  also,  a  competent  foreman  constantly  on  th«> 
ground.  He  is  to  provide  all  labor,  transportation,  materials,  apparatus,  scaffold- 
ing and  utensils  necessary  for  the  complete  and  substantial  execution  of  everything 
described,  shown  or  reasonably  implied  in  the  drawings  and  specifications. 

All  material  and.  workmanship  to  be  of  the  best  quality  throughout. 

The  contractor  must  carefully  lay  out  his  work  and  be  responsible  for  any  mis- 
takes he  may  make,  and  any  injury  to  others  resulting  from  them. 

Where  no  figures  or  memoranda  are  given,  the  drawings  shall  be  accurately  fol- 
lowed according  to  their  scale  ;  but  figures  or  memoranda  are  to  be  preferred  co 
the  scale  in  all  cases  of  difference. 

In  any  and  all  cases  of  discrepancy  in  figures,  the  matter  shall  be  immediately 
submitted  to  the  architects  for  their  decision,  and  without  such  decision  said  dis- 
crepancy shall  not  be  adjusted  by  the  contractor  save  and  only  at  his  own  risk  ; 
and  in  the  settlement  of  any  complications  arising  from  such  adjustment,  the  con- 
tractor shall  bear  all  the  extra  expenses  involved. 

The  plans  and  these  specifications  are  to  be  considered  co-operative ;  and  all 
works  necessary  to  the  completion  of  the  design,  drawn  on  plans,  and  not  described 
herein,  and  all  works  described  herein  and  not  drawn  on  plans,  are  to  be  consid- 
ered a  portion  of  the  contract,  and  must  be  executed  in  a  thorough  manner,  with  the 
best  of  materials,  the  same  as  if  fully  specified. 

The  architects  will  supply  full-size  drawings  of  all  details,  and  any  work  con- 
structed without  such  drawings,  or  not  in  accordance  with  them,  must  be  taken 
down  and  replaced  at  the  contractor's  expense. 

Any  material  delivered  or  work  erected  not  in  accordance  with  the  plans  and 
these  specifications  must  be  removed  at  the  contractor's  expense  and  replaced  with 
other  material  or  work,  satisfactory  to  the  architects,  at  any  time  during  the  pro- 
gress of  the  work.  Or  in  case  the  nature  of  the  defects  shall  be  such  that  it  is  not 


372  BUILDING  CONSTRUCTION. 

expedient  to  have  it  corrected,  the  architects  shall  have  the  right  to  deduct  such 
sums  of  money  as  he  considers  a  proper  equivalent  for  the  difference  in  the  value 
of  the  materials  or  work  from  that  specified,  or  the  damage  to  the  building,  from 
the  amount  due  the  contractor  on  the  final  settlement  of  the  accounts. 

The  contractor  will  provide  proper  and  sufficient  safeguards  and  protection 
against  the  occurrence  of  any  accidents,  injuries,  damages  or  hurt  to  any  person  or 
property  during  the  progress  of  the  work,  and  shall  be  alone  responsible,  and  not 
the  owner  or  the  architects,  who  will  not  in  any  manner  be  answerable  for  any  loss 
or  damage  that  may  happen  to  the  work,  or  any  part  thereof,  or  for  any  of  the 
materials  or  tools  used  and  employed  in  finishing  and  completing  the  work. 

The  contractor  must  produce,  when  called  upon  by  the  architects,  vouchers  from 
the  sub-contractors  to  show  that  the  work  is  being  paid  for  as  it  proceeds. 

Every  facility  must  be  given  the  architects  for  inspecting  the  building  in  safety, 
such  as  ladders,  scaffolding  and  gangways,  and  provision  to  be  made  to  the  archi- 
tects' satisfaction  for  protection  from  falling  materials. 

The  drawings  are  the  property  of  the  architects  and  must  be  returned  to  them 
before  the  final  payment  is  made. 

The  contractor  is  to  keep  the  building  at  all  times  free  from  rubbish  and  shav- 
ings, and  on  completon  to  remove  all  rubbish  and  waste  material  caused  by  any  oper- 
ations under  his  charge,  clean  up  the  house  and  grounds,  and  leave  the  wor1-.  per- 
fect in  every  respect. 

EXCAVATING  AND  GRADING. 

374- — The  contractor  shall  visit  the  site  of  the  building  and  examine  for  him- 
self the  condition  of  the  lot,  and  satisfy  himself  as  to  the  nature  of  the  soil. 

[Where  this  is  not  practicable  the  architect  should  show  the  pres- 
ent grade  of  lot  by  red  lines  on  the  elevation  drawings,  and  the 
nature  of  the  soils  should  be  determined  by  borings  or  test  pits.  See 
Section  4.] 

Loam. — This  contractor  is  to  remove  the  present  top  soil  to  the  depth  of  12  inches 
from  the  site  of  the  building  and  for  (20)  feet  on  each  side,  and  stack  where  indi- 
cated on  the  lot. 

Excavate  to  the  depth  shown  by  the  drawings  for  the  cellar,  areas,  coal  vault 
and  outside  entrance,  and  for  trenches  under  all  walls  and  piers.  All  trenches 
shall  be  excavated  to  the  neat  size  as  far  as  practicable,  and  each  shall  be  leveled 
to  a  line  on  the  bottom,  ready  to  receive  the  foundation.  This  contractor  must  be 
careful  not  to  excavate  the  trenches  below  the  depth  shown  by  the  drawings  ; 
should  he  do  so  he  must  pay  the  mascn  for  the  extra  mason  work  thereby  made 
necessary,  as  under  no  condition  will  dirt  filling  be  allowed. 

All  excavations  to  be  kept  at  least  (12)  inches  outside  the  outer  face  of  walls. 
(See  Section  31.) 

[Excavations  for  drains,  dry  wells,  furnace  pit,  air  ducts,  etc.,  to 
be  specified  here  if  required.] 

Water. — Should  water  be  encountered  in  making  the  excavations,  this  con- 
tractor is  to  keep  it  pumped  out  of  the  way  until  the  footings  are  set,  unless  practi- 
cable to  drain  into  sewer. 


SPECI PICA  TIGNS.  3  7  3 

Stone. — Should  a  solid  ledge  be  encountered  in  the  excavations,  this  contractor 
is  to  remove  the  same  by  blasting  or  other  process,  and  is  to  pile  the  stone  where 
directed  on  the  lot  (if  suitable  for  foundation).  For  removing  such  stonework  an 

extra  sum  of  ( cents)  per  cubic  foot  of  stone  excavation  will  be  paid,  but  no 

extra  payment  will  be  made  for  removing  boulders  or  loose  stones. 

Remove  from  the  premises  as  soon  as  excavated  all  material  except  the  loam 
and  such  as  may  be  needed  for  filling  about  the  walls  (or  grading). 

Filling. — When  directed  by  the  architect,  this  contractor  shall  fill  about  the 
walls  (with  stone,  gravel  or  sand)  to  within  (3)  feet  (half  their  height)  of  the  fin- 
ished grade,  and  as  soon  as  the  first  floor  joist  are  set  he  shall  complete  the  filling 
to  the  grade  line,  tamping  the  earth  solidly  every  6  inches.  (See  Section  87  ) 

Grading. — Grade  the  surface  of  the  lot  to  the  level  indicated  by  the  drawings 
(using  the  loam  first  removed)  and  leave  in  good  condition  for  top  dressing  (or  pav- 
ing.) (Foundations  for  walks  and  driveways.) 

[When  building  on  a  site  formerly  occupied  by  a  building,  or  cov- 
ered with  rubbish,  the  specifications  should  provide  for  the  removal 
of  all  rubbish,  debris,  old  foundation  stone,  sidewalk  stone  and  other 
materials  that  cannot  be  used  in  the  new  building.] 

PILING. 

375* — This  contractor  is  to  furnish  and  drive  the  piles  indicated  on  sheet  (i). 

All  piles  shall  be  of  sound  (white  oak,  yellow  pine,  Norway  pine  or  spruce). 
They  must  be  at  least  (6)  inches  in  diameter  at  the  head  and  (10)  inches  at  the  butt 
when  sawn  off,  and  must  be  perfectly  straight  and  trimmed  close  and  have  the 
bark  stripped  off  before  they  are  driven.* 

The  piles  must  be  driven  into  hard  bottom  or  until  they  do  not  move  more  than 
\  inch  under  the  blow  of  a  hammer  weighing  (2,000)  pounds,  falling  (25)  feet  at  the 
last  blow.  They  must  be  driven  vertically  and  at  the  distances  apart  required  by 
the  plans. 

They  must  be  cut  off  square  at  the  head,  and,  when  necessary  to  prevent  broom- 
ing, shall  be  bound  with  iron  hoops. 

All  piles,  when  driven  to  the  required  depth,  shall  be  cut  off  square  and  hori- 
zontal at  the  grade  indicated  on  the  drawings  by  this  contractor. 

(See  Sections  35,  36  and  37.) 

CONCRETE  FOOTINGS. 

37^' — All  footings  colored  (purple)  on  the  foundation  plan  and  sections  shall 
be  constructed  of  concrete  furnished  and  put  in  place  by  this  contractor. 

If  the  trenches  are  not  excavated  to  the  neat  size  of  the  footings,  or  where  the  con- 
crete is  above  the  level  of  cellar  floor,  this  contractor  shall  set  up  2-inch  plank,  sup- 
ported by  stakes  or  solidly  banked  with  earth  to  confine  the  concrete,  and  these  planks 
are  not  to  be  removed  until  the  concrete  is  (48)  hours  old. 

The  concrete  shall  be  composed  of  first-quality  fresh  (Atlas)  cement,  clean,  sharp 
sand  and  clean  (granite)  broken  to  a  size  that  will  pass  through  a  2^-inch  ring,  and 
thoroughly  screened.  These  ingredients  shall  be  used  in  the  proportion  of  i  part 

*  This  latter  clause  is  not  always  required. 


374  BUILDING  CONSTRUCTION. 

cement,  2  of  sand  and  4  of  stone,  and  mixed  each  time  by  careful  measurement,  in 
the  following  manner :  On  a  tight  platform  of  plank  spread  four  barrows  of  sand, 
and  upon  this  two  barrows  of  cement.  Thoroughly  mix  the  two  dry,  and  then  throw 
on  eight  barrows  of  broken  stone  and  work  over  again  ;  then  work  thoroughly  and 
rapidly  with  shovels  while  water  is  being  turned  on  with  a  hose,  until  each  stone  is 
completely  covered  with  mortar.  No  more  water  to  be  used  than  is  necessary  to 
unite  the  materials.  As  soon  as  the  concrete  is  mixed  it  is  to  be  taken  to  the  trenches 
and  dumped  in  layers  about  6  inches  thick,  and  immediately  rammed  until  the  water 
flushes  to  the  top.  The  next  layer  must  be  put  on  before  the  preceding  one  becomes 
dry,  and  the  top  be  well  wet  before  putting  in  the  new  layer.  The  stone  footings  shall 
not  be  put  on  the  concrete  until  it  is  two  days'  old.  (See  Sections  140,  145.) 

[On  large  and  important  work  the  specifications  should  also  pro- 
vide for  testing  the  cement.  (See  Section  125.)  The  above  quanti- 
ties are  as  much  as  should  be  mixed  at  one  time.] 

SPECIFICATIONS  FOR  STONEWORK. 

377- — Footings.— Supported  on  Piles. — The  pile  capping  to  be  of  even  split 

granite  blocks  (16)  inches  thick  from  quarries,  to  be  of  such  size  that  no 

stone  will  rest  on  more  than  three  piles,  and  to  be  bonded  as  shown  on  special  draw- 
ing. Each  and  every  stone  is  to  be  carefully  wedged  up  with  oak  wedges  on  the 
head  of  each  pile  to  secure  a  firm  and  equal  bearing,  and  are  to  butt  closely  together. 

Dimension  footings. — The  footings  under  all  outside  foundation  walls  are  to  con- 
sist of  dimension  stone  from  the or  —  —  quarries,  of  the  width  shown  on 

the  section  drawings  and  (12)  inches  thick.  To  have  fair  surfaces  top  and  bottom, 
and  to  be  bedded  and  puddled  in  cement  mortar.  No  footing  stone  to  be  less  than 
(3)  feet  long. 

Rubble  Footings. — Build  the  footings  under  (all  other)  foundation  walls  of  the 

vidth  and  thickness  shown  by  section  drawings,  of^ stone.  The  stone  to  be 

heavy  rubble,  each  stone  to  be  of  the  full  thickness  of  the  footing  course,  at  least  2 
feet  6  inches  long,  and  not  more  than  t\vo  stones  abreast  in  the  width  of  the  wall; 
there  shall  also  be  one  through  stone,  the  full  width  of  the  footings,  every  (6)  lineal 
feet.  Each  stone  is  to  be  solidly  bedded  and  puddled  in  cement  mortar,  and  all 
chinks  between  the  stones  are  to  be  filled  solid  with  mortar  and  spalls. 

378. — Foundation  Walls. — Block  Granite  or  Limestone. — Build  the  founda- 
tion walls  colored  (blue)  on  plans  to  the  height  and  thickness  shown  by  section  draw- 
ings, of  sound,  even,  split  granite  (limestone)  blocks  to  average  (3)  feet  in  length,  (18) 
inches  wide  and  to  be  not  less  than  (12)  inches  in  height.  To  be  laid  with  a  good 
bond  in  regular  courses,  as  near  as  can  be,  and  bonded  with  one  through  stone  in 
every  (10)  square  feet  of  wall 

The  stone  to  be  laid  in  cement  mortar,  as  described  elsewhere,  all  chinks  and 
voids  to  be  filled  with  slate  or  (granite)  spalls  and  mortar,  to  show  a  good  straight  face 
where  exposed  in  the  basement,  and  the  joints  to  be  neatly  pointed  with  the  trowel. 
All  walls  must  be  built  to  a  line  both  inside  and  outside,  and  all  angles  to  be  plumb. 
(Inside  face  of  wall  to  be  hammer-dressed.)  Top  of  wall  to  be  carefully  leveled  for 
the  superstructure,  with  heavy  stones  at  each  corner.  Leave  holes  in  wall  for  drain, 
gas  a:.d  water  pipes. 


SPECIFICA  TIONS.  3  7  5 

Rubble  Walls. — Build  the  foundation  and  basement  walls  colored  (gray)  on  plans 

to  the  height  and  thickness  shown  on  section  drawings,  of stone  rubble.  To 

be  of  selected,  large  size,  first  quality  stone,  laid  to  the  lines  on  both  sides,  well  fitted 
together,  and  all  voids  filled  solid  with  spalls  and  mortar.  Each  stone  to  be  firmly 
bedded  and  cushioned  into  place,  and  all  joints  shall  be  filled  with  mortar.  At  least 
half  of  the  stones  are  to  be  two-thirds  the  width  of  the  wall,  and  there  shall  be  one 
through  stone  to  every  (10)  square  feet  of  wall.  The  larger  part  of  the  stones  shall 
be  not  less  than  (2  feet)  long,  (16  inches)  wide  and  (8  inches)  thick.  The  wall  to  be 
laid  in  courses  about  (18  inches)  high  and  leveled  off  at  each  course.*  (Each  stone 
shall  have  hammer-dressed  beds  and  joints,  and  the  face  of  the  stone  showing  on  the 
inside  of  the  wall  shall  be  coarse  bush-hammered,  f)  The  wall  to  be  built  plumb  and 
carefully  leveled  on  top  to  receive  the  superstructure. 

Cementing  Outside  of  Wall. — As  soon  as  the  wall  is  completed  the  contractor  is 
to  rake  out  all  loose  mortar  in  the  outside  joints  and  plaster  the  entire  outside  of  the 
wall  (except  where  exposed  in  areas)  with  Dyckerhoff  Portland  cement  mortar  not  less 
than  \  inch  thick.  The  mortar  to  be  mixed  in  the  proportion- of  i  to  i.  Area  walls 
to  have  the  joints  raked  out  and  pointed  with  cement  mortar,  and  a  false  joint  of  red 
cement  mortar  run  with  a  jointer  and  straight-edge.  The  trench  is  not  to  be  refilled 
until  the  wall  has  been  plastered  at  least  twenty-four  hours. 

Basement  Piers. — All  piers  colored  (blue)  on  basement  plan  to  be  built  of 

stone,  and  each  stone  shall  be  of  the  full  size  of  the  pier  \  laid  on  its  natural  bed,  and 
the  top  and  bottom  of  each  stone  to  be  cut  so  as  to  form  joints  not  exceeding  ^  inch 
in  width.  All  four  sides  of  pier  to  be  rough  pointed  and  all  corners  to  be  pitched 
off  to  a  line.  The  top  stone  to  be  dressed  to  receive  the  iron  plate  resting  on  the  pier 
and  each  stone  to  be  solidly  bedded  in  cement  mortar  as  specified  elsewhere. 

Mortar. — All  stone  masonry  above  referred  to  shall  be  laid  in  mortar  composed  of 

perfectly  fresh  (Rosendale)  cement, brand,  mixed  in  the  proportion  of  i  part 

cement  to  (2)  parts  of  clean,  sharp  sand.  The  sand  and  cement  shall  be  mixed  dry 
in  a  box,  then  wet,  tempered  and  immediately  used.  (See  Section  128.)  No  mortar 
that  has  commenced  to  set  to  be  used  on  the  work. 

379-— External  Stone  Walls.— Rubble.— Build  the  external  walls  (in  first 
story)  of  rubble  from  the  quarries.  To  be  laid  random,  with  hammer- 
dressed  joints,  and  the  outside  face  split  so  that  the  projection  shall  not  exceed  2 
inches.  The  stones  to  be  laid  on  their  natural  bed,  with  good  vertical  bond,  and  to 
be  one  through  stone  in  every  10  square  feet  of  wall.  All  stones  showing  on  the 
exterior  to  be  selected  from  the  largest  in  the  pile,  and  as  few  spalls  to  be  used  as 
possible.  Every  stone  to  be  well  bedded  in  mortar,  made  of  i  part  (Rosendale) 
cement  and  (2)  parts  clean,  sharp  sand,  and  all  joints  and  chinks  filled  solid  with  mor- 
tar and  spalls.  All  inside  joints  to  be  smoothly  pointed  with  the  trowel  as  the  wall 
is  built.  After  the  wall  is  built  the  joints  on  the  outside  are  to  be  raked  out  and 
filled  with  cement  mortar,  and  a  false  joint  of  red  Portland  cement  mortar  run  with 
a  jointer  and  straight-edge,  in  imitation  of  broken  ashlar. 

*  This  is  unnecessary  in  ordinary  foundations  for  dwellings. 

+  Only  required  in  places  where  a  neat  and  extra  strong  wall  is  required.  This  is  expensive 
work. 

%  Or,  in  courses  varying  from  8  to  12  inches  in  height,  every  other  course  to  be  the  full  size  of 
the  pier  and  the  intermediate  course  to  consist  of  two  stones,  each  one-half  the  size  of  the  pier. 
Each  stone  to  be  laid  on  its  natural  bed,  etc. 


376  BUILDING  CONSTRUCTION. 

Field  Rubble.—  The  external  wall  of  (first  story)  is  to  be  faced  with  round  field 
stones,  selected  for  their  color,  and  the  moss  and  lichens  left  on.  The  stones  to  be 
fitted  together  according  to  their  size  and  without  spalls.  The  back  and  sides  to  be 
split  with  the  hammer  where  necessary  to  give  a  bond,  and  the  stones  to  have  their 
long  axis  crossways  of  the  wall  and  to  be  laid  in  cement  mortar.  The  wall  to  be 
backed  up  with  split-face  rubble  carefully  bonded  to  the  facing. 

CUT  STONEWORK. 

3oO. — Granite. — All  trimmings  colored  blue  on  the  elevation  drawings  to  be  of 
(Quincy)  granite.  The  stock  to  be  carefully  selected  and  free  from  all  natural  imper- 
fections, such  as  mineral  stains,  sap  or  other  discolorations  ;  to  be  of  an  even  shade 
of  color  throughout,  so  that  one  stone  shall  not  look  of  a  different  shade  from  another 
when  set  in  place. 

The  face  of  sills,  caps,  quoins  and  water  table,  where  so  indicated  on  the  elevation 
drawings,  to  be  pitched  face,  with  i-inch  angle  margin  on  the  quoins  and  water 
table.  All  steps  and  thresholds  to  be  hammered  work,  six-cut,  and  the  balance  of 
the  trimmings  to  be  best  eight-cut  work. 

Sandstone. — All  trimmings  shown  by  brown  color  on  the  elevation  drawings  to  be 
of  best  quality  selected  (Cleveland)  buff  sandstone,  of  uniform  color  and  hardness, 
free  from  sand  holes  and  rust,  and  cut  so  as  to  lay  on  its  natural  bed  when  set  in  the 
wall.  All  stone  trimmings  thus  shown  are  to  be  worked  in  strict  accordance  with 
the  detail  drawings,  with  true  surfaces  and  good  sharp,  straight  lines;  and  all  stone 
belts,  unless  otherwise  provided  for,  are  to  have  a  bearing  upon  the  walls  of  at  least 
(6)  inches,  and  the  projecting  courses  to  have  a  bearing  of  2  inches  more  than  the  pro- 
jection. All  exposed  surfaces  of  the  sandstone  are  to  be  carefully  tooled,  (rubbed). 
or  (crandalled),  the  workmanship  being  regular  and  uniform  in  every  part  and  done 
in  a  skillful  manner.  All  mouldings  to  be  carefully  fitted  together  at  the  joints,  and, 
no  horizontal  or  vertical  joint  to  exceed  T\  of  an  inch.  All  return  heads  at  the  angles, 
etc.,  are  to  be  at  least  (12)  inches.  No  patching  of  any  stone  will  be  allowed. 

[Ordinary  soft  sandstones,  or  "  freestones,"  are  not  suitable  for 
steps  and  door  sills,  which  should  be  either  of  granite  or  some  hard 
sand  or  limestone.] 

Ashlar. — The  (south)  and  (west)  walls  of  the  building  where  exposed  above  the 
(water  table)  are  to  be  faced  with  coursed  (broken)  ashlar  of  the  same  stone  as  specified 
for  the  trimmings.  The  ashlar  to  be  in  courses  (12)  inches  high,  except  as  otherwise 
shown  on  elevation  drawings,  and  to  have  plumb  bond  wherever  practicable.  (The  sur- 
face of  the  quoins  to  be  raised  i  inch  from  the  face  of  the  wall,  with  beveled  or  rusticated 
joints,  and  the  faces  of  the  stones  to  be  rusticated  in  a  skillful  manner.  Each  quoin 
to  be  (i6)x(24)  inches,  reversed  as  shown  on  drawings.)  The  balance  of  the  ashlar 
to  be  rubbed  to  a  true  surface,  without  wind,  cut  to  lie  upon  its  natural  bed,  and  for 
T\-inch  joints.  No  stone  to  be  less  than  4  inches  thick,  and  at  least  one  jamb  stone 
to  each  opening  to  extend  through  the  wall.  All  mullions  16  inches  or  less  in  width 
to  be  cut  the  full  thickness  of  the  wall. 

The  contractors,  both  for  the  granite  and  sandstone,  are  to  do  all  drilling,  lewising, 
fitting  and  other  jobbing  required  for  setting  the  stone  or  to  receive  iron  ties,  clamps, 
etc.,  and  are  to  provide  all  patterns  necessary  and  required  for  the  execution  of  the. 
work. 


SPECIFIC  A  TIONS.  3  7  7 

Setting  Stonework. — [The  specifications  should  distinctly  state  who 
is  to  set  the  stonework.  If  the  stonework  consists  of  a  few  trim- 
mings only  it  will  be  cheaper  for  the  brick  mason  to  set  it,  but  if  there 
is  much  stonework  it  should  be  set  by  the  stone  mason.] 

All  stonework  shown  by  blue  or  brown  color  on  the  elevation  drawings,  and  as 
previously  specified,  is  to  be  set  in  the  best  manner  by  this  contractor  in  mortar  mixed 
in  the  proportions  of  2  parts  of  (Rockland)  lime  mortar  and  I  part  fresh  (Rosendale) 
cement.  The  cement  to  be  mixed  with  the  lime  mortar  in  small  quantities  and  in  no 
case  shall  any  be  used  that  has  stood  over  night.  (For  setting  limestone  and  marble 
see  Section  208.) 

As  the  stone  is  delivered  at  the  building  the  mason  will  accept  the  same  and  be 
held  responsible  therefor  until  the  full  completion  of  his  contract ;  any  damage 
that  may  occur  to  any  stone,  whether  on  the  ground  or  in  the  building,  during  the 
said  period,  shall  be  made  good  at  his  own  expense  and  to  the  satisfaction  of  the 
architect  or  superintendent. 

The  mason  must  call  upon  the  carpenter  to  box  or  otherwise  protect  by  boards  all 
steps,  mouldings,  sills,  carving  and  any  other  work  liable  to  be  injured  during  the 
construction  of  the  building. 

Every  stone  to  be  carefully  set,  joints  left  open  under  centre  of  sills  and  at  the  outer 
edges  of  all  stonework,  and  all  stones  to  be  uniformly  bedded,  joints  kept  level  and 
plumb  and  of  uniform  thickness.  The  mason  is  to  provide  derricks  and  all  other 
apparatus  necessary  to  set  the  stone  properly,  and  is  to  carry  on  the  work  so  as  not  to 
delay  the  other  mechanics.  Where  the  stone  is  backed  up  with  brick  the  stone  shall 
not  be  set  more  than  two  courses  ahead  of  the  backing. 

Anchors  and  Clamps. — This  contractor  is  to  provide  all  necessary  iron  anchors  and 
clamps  (which  are  to  be  galvanized  or  dipped  in  tar)  for  securing  the  stone  as  herein, 
specified  or  as  directed  by  the  superintendent. 

Each  piece  of  ashlar  12  inches  or  more  in  height  is  to  have  one  iron  anchor 
extending  through  the  wall,  and  when  exceeding  4  feet  in  length  two  clamps  are  to 
be  used.  (Broken  ashlar  will  be  bonded  by  through  stones,  one  to  every  10  square  feet 
of  wall.)  Also  anchor  all  projecting  stones,  corbels,  finials,  etc.,  with  iron  anchors 
satisfactory  to  the  superintendent.  All  coping  stones  and  other  horizontal  string 
courses  or  cornices,  where  so  indicated  by  notes  on  the  drawings,  are  to  be  clamped 
together. 

Cleaning  and  Pointing. — After  all  the  stonework  is  set  complete  (and  the  roof  is 
on)  the  mason  shall  scrub  down  with  muriatic  acid  and  water,  using  a  stiff  bristle 
brush,  all  stonework,  rake  out  all  joints  to  the  depth  of  i  inch  and  repoint  with  Port- 
land cement  and  (Clinton)  red,  well  driven  into  the  joint  and  rubbed  smooth  with 
the  jointer  with  half  round  raised  joint  as  per  marginal  sketch.  (It  will  be  well  to 
show  in  margin  the  kind  of  joint  desir  ed ;  see  also  Section  209). 

The  entire  work  to  be  left  clean  and  perfect  on  completion  of  the  contract. 

SPECIFICATIONS  FOR  BRICKWORK. 

38l. — This  contractor  is  to  furnish  all  materials,  including  water,  and  all 
labor,  scaffolding  and  utensils  necessary  to  complete  the  brickwork  indicated  by 
red  color  on  the  plans  and  sections,  and  as  shown  by  the  elevations  and  as  herein 
specified. 


378  BUILDING  CONSTRUCTION. 

Face  Work. — Pressed  Brick. — The  exposed  surfaces  of  the  building  (on  south 
and  east  elevations),  including  the  chimneys,  to  be  faced  with  (St.  Louis)  pressed 
brick  like  the  sample  in  architect's  office  ;  all  to  have  good  sharp  edges  and  to  be  of 
uniform  size  and  color. 

Moulded  Brick. — Furnish  all  moulded  brick  shown  on  elevation  drawings  and 

as  indicated  by  numbers  (which  refer  to 's  catalogue).     These  brick  to  be  as 

near  the  color  of  the  pressed  brick  as  can  be  obtained,  and  laid  to  give  as  even  lines 
as  possible.  Furnish  octagon  brick  for  the  external  angles  of  bays  and  circular 
brick  of  proper  curvature  for  the  circular  bay  (or  tower). 

Stock  Brick. — The  exposed  surfaces  of  the  brickwork  (on  west  elevation)  to  be 
of  best  quality  dark  red  stock  brick,  with  good  sharp  corners  and  square  edges. 

Common  Brick. — The  balance  of  the  exposed  brickwork  to  be  of  selected,  even- 
colored  common  brick,  as  nearly  uniform  in  size  and  color  as  can  be  obtained,  and 
carefully  culled. 

All  face  brick  to  be  laid  in  the  most  skillful  manner  (from  an  outside  scaffold) 
in  colored  mortar,  as  specified  elsewhere.  Each  brick  to  be  dipped  in  water  before 
laying ;  each  edge  of  the  brick  and  down  the  middle  to  be  butted,  and  all 
vertical  joints  to  be  filled  solid  from  front  to  back.  The  brick  to  be  laid  with 
plumb  bond  and  bonded  to  the  backing  with  a  diagonal  header  to  every  brick  in 
every  (fifth)  course.  [Or  bonded  with  the  Morse  tie,  one  tie  laid  over  every  brick 
i  in  every  fourth  course.]  In  piers  only  solid  headers  to  be  used. 

All  courses  to  be  gauged  true,  and  all  joints  to  be  rodded  (or  struck  with  a  bead 
jointer.  See  Section  237). 

The  returns  of  pressed  brickwork  must  be  carefully  dovetailed  into  the  common 
brickwork  or  bonded  by  solid  headers. 

Ornamental  Work. — All  brick  cornices,  belt  courses,  arches,  chimney  tops  and 

other  ornamental  brick  features  of  the  building  must  be  laid  up  in  the  most  artistic 

and  substantial  manner,  according  to  the  scale  and  detail  drawings.     All  arches  to 

be  bonfled  and  the  bricks  cut  and  rubbed  so  that  each  joint  will  radiate  from  the 

'     centre.     (Arch  brick  are  often  specified  for  first-class  work  in  large  cities.) 

Common  Brickwork. — All  other  brickwork  to  be  laid  up  with  good  hard-burned 
(the  best  merchantable)  common  bricks,  acceptable  to  the  architect,  in  mortar,  as 
specified  elsewhere. 

All  brick  shall  be  well  wet,  except  in  freezing  weather,  before  being  laid. 

Each  brick  shall  be  laid  with  a  shove  joint  in  a  full  bed  of  mortar,  all  interstices 
being  thoroughly  filled,  and  where  the  brick  comes  in  connection  with  anchors  each 
one  shall  be  brought  home  to  do  all  the  work  possible. 

Up  to  and  including  the  fourth  story  every  fourth  course  shall  consist  of  a  head- 
ing course  of  whole  brick,  extending  through  the  entire  thickness  of  the  wall  or 
backing ;  above  the  fourth  story  every  sixth  course  shall  be  a  heading  course. 
|         All  mortar  joints,  where  the  wall  is  not  to  be  plastered,  shall  be  neatly  struck, 
|    as  is  customary  for  first-class  trowel  work.     All  courses  of  brickwork  shall  be  kept 
level,  and  the  bonds  shall  be  accurately  preserved.     When  necessary  to  bring  any 
I    courses  to  the  required  height,  clipped   courses  shall  be  formed  (or  the  bricks  laid 
on  edge),  as  in  no  case  shall  any  mortar  joints  finish  more  than  \  inch  thick.     All 
brickwork  shall  be  laid  to  the  lines,  and  all  walls  and  piers  must  be  built  plumb, 
true  and  square.     Walls  to  be  carefully  leveled  for  floor  joist. 

L 


SPECIFIC  A  TIONS.  3  7  9 

All  cut  stone  shall  be  backed  up  as  fast  as  the  superintendent  shall  direct,  and  the 
brick  mason  shall  build  in  all  anchors  that  may  be  furnished  by  the  contractor  for 
the  cut  stonework,  or  by  the  carpenter  or  iron  contractor.  m 

All  partition  walls  to  be  tied  to  the  outside  walls  by  iron  anchors  (furnished  by 
this  contractor),  y^xif  inches  in  section  and  (3  feet  6  inches)  long,  built  into  the 
walls  every  (4)  feet  in  height. 

When  openings  or  slots  are  indicated  in  the  brick  walls,  the  size  and  position  of 
the  same  shall  be  such  as  the  superintendent  shall  direct,  unless  otherwise  shown. 
This  contractor  shall  leave  openings  to  receive  all  registers  that  may  be  required  in 
connection  with  the  heating  or  ventilating  system. 

Firmly  bed  and  fill  in  around  all  timbers,  point  around  all  window  frames,  inside 
all  staff  beads  and  window  sills,  and  wherever  required,  and  bed  all  wall  plates  in 
mortar  on  the  brickwork. 

Protection. — This  contractor  shall  carefully  protect  his  work  by  all  necessary 
bracing,  and  by  covering  up  all  walls  at  night  or  in  bad  weather.  (He  shall  protect 
all  mason  work  from  frosts  by  covering  with  manure  or  other  materials  satisfactory 
to  the  superintendent. 

The  top  of  all  walls  injured  by  the  weather  shall  be  taken  down  by  this  contractor 
at  his  expense  before  recommencing  the  work. 

Hollow  Fire  Clay  Brick  (for  buildings  of  skeleton  construction). — All  brick  used  in 
connection  with  the  spandrels  above  the  first  story  on  all  elevations,  together  with 
all  backing  required  in  connection  with  the  stone  or  terra  cotta  work  above  the  (sixth) 
story  floor  beams,  shall  consist  of  first  quality  hard-burned  fire  clay,  hollow  brick, 
equal  in  quality  to  sample  in  the  architect's  office.  Each  brick  shall  be  laid  with  a 
shove  joint  and  the  work  well  bonded.  The  inside  surface  of  the  wall  to  be  left 
smooth,  true  and  ready  for  plastering. 

Mortar. — Cement  Mortar. — All  brickwork  below  the  grade  line  arid  the  last  five 
courses  of  chimneys  and  parapet  walls  shall  be  laid  in  mortar  composed  of  i  part 
fresh  (Rosendale*)  cement  and  (2)  parts  clean,  sharp  bank  sand,  properly  screened, 
mixed  with  sufficient  water  to  render  the  mixture  of  proper  consistency.  Care  must 
be  taken  to  thoroughly  mix  the  sand  and  cement  dry.  in  the  proportions  specified, 
before  adding  the  water.  The  mortar  shall  be  mixed  in  small  quantities  only,  and 
in  no  case  shall  mortar  that  has  commenced  to  set.  or  stood  over  night  be  used.  (See 
Section  128.) 

[In  Colorado,  and  possibly  in  some  other  localities,  a  gray  hydraulic 
lime  is  obtained,  which  answers  about  as  well  as  cement  for  founda- 
tion walls.] 

Lime  and  Cement  Mortar. — All  common  brickwork  in  (first  and  second)  stories     \  y»<vJr 
to  be  laid  in  mortar  composed  of  (3)  parts  of  lime  mortar,  having  a  large  proportion     \      „ 
of  sand  and  i  part  of  fresh  (Utica)  cement.     The  lime  mortar  to  be  worked  at  least 
two  days  before  the  cement  is  added,  and  only  small  quantities  of  cement  to  be  mixed 
at  a  time  (see  Section  131.) 

Lime  Mortar. — The  balance  of  the  common  brickwork  to  be  laid  in  mortar  com- 
posed of  fresh-burned  (Rockland)  (Missouri)  lime  and  clean,  sharp  sand,  well 
screened.  (No  loam  to  be  used.)  The  lime  and  sand  to  be  mixed  to  make  a  rich 


1  Or  any  of  the  cements  described  in  Section  n 


r 


380  BUILDING  CONSTRUCTION. 

mortar,  satisfactory  to  the  architect.  Lime  that  has  commenced  to  slake  shall  not  be 
used. 

Colored  Mortar. — All  face  brick  to  be  laid  in  mortar  composed  of  lime  putty  and 
finely-sifted  sand,  colored  with  (Pecoria)  or  (Peerless)  mortar  stains ;  colors  to  be 
selected  by  the  architect. 

Grouting. — All  brick  footings  and  the  piers  in  basement  must  be  grouted  in  every 
course  and  flushed  full  with  cement  mortar,  as  specified  above. 

Cement  Plastering. — The  outside  of  all  brick  walls  that  come  in  contact  with  the 
earth  shall  be  smooth  plastered  by  this  contractor,  from  bottom  of  footings  to  grade 
line,  with  (Atlas)  Portland  cement  mortar,  mixed  in  the  proportion  of  i  to  2,  and  of 
an  average  thickness  of  \  inch. 

Plaster  the  top  of  all  projecting  brick  belt  courses,  and  the  tops  of  fire  walls,  where 
not  otherwise  protected,  with  the  same  kind  of  mortar,  being  careful  to  make  a  neat 
job.  (See  Section  240.) 

Relieving  Arches. — Turn  three  rowlock  relieving  arches  ever  all  door  and  win- 
dow openings  behind  the  face  arch  or  lintel.  These  arches  to  have  a  brick  core, 
and  to  spring  from  beyond  the  ends  of  wood  lintel. 

Chimneys. — Build  all  chimneys  and  vent  flues  as  shown  by  drawings,  and  top  out 
as  shown  on  elevation  drawings. 

All  withes  to  be  4  inches  thick,  well  bonded  to  the  walls,  and  the  flues  to  be  car- 
rie'd  up  separately  to  the  top.  Plaster  the  inside  of  all  flues  (unless  provided  with 
flue  lining)  from  bottom  to  top  with  (Portland  cement)  mortar,  and  plaster  the  out- 
side of  the  flues  where  they  pass  through  the  floors. 

Slides  (slanting  boards)  must  be  put  in  each  flue  at  the  bottom,  with  an  opening 
above  to  carry  out  the  mortar  droppings,  and  on  completion  of  the  chimneys  the  flues 
must  be  thoroughly  cleaned  out  and  the  openings  bricked  up. 

All  brick  chimney  breasts  to  be  built  olumb,  straight  and  true,  and  all  corners 
square. 

Build  rough  openings  for  fireplaces  (with  -|x2-inch  iron  arch  bars,  turned  up  2 
inches  at  the  ends)  and  turn  trimmer  arches  to  the  same  2  feet  wide  on  wooden  cen- 
tres furnished  and  set  by  the  carpenter. 

Build  the  ash  pits  under  grates,  as  shown  by  plans,  and  provide  and  set  a  cast  iron 
ash  pit  door  and  frame  in  each  pit  where  shown  or  directed. 

Flue  Lining. — Furnish  and  set  in  (the  range  and  furnace  flues)  8xi2-inch  fire 
clay  flue  linings  to  start  (2  feet)  below  the  thimble  and  continued  to  the  top  of  flue. 
The  lining  to  be  set  in  rich  lime  (cement)  mortar,  with  joints  scraped  clean  on  the 
inside. 

Thimbles. — Provide  and  set  in  all  flues,  except  grate  flues,  (sheet)  iron  thimbles, 
8  inches  in  diameter  in  furnace  flue  and  6  inches  elsewhere,  to  be  set  2  feet  below 
the  ceiling  unless  otherwise  directed.  Furnish  bright  tin  stoppers  for  all  thimbles 
except  for  (range  and  furnace.) 

Cold  Air  Duct. — Excavate  for  and  build  the  cold  air  duct  and  foundation  for  fur- 
nace as  shown  by  drawings  of  hard-burned  brick,  laid  in  (Rosendale)  cement  mor- 
tar, and  plastered  smooth  on  the  inside;  also  plaster  the  bottom  of  duct  and  furnace 
pit  with  cement  mortar,  on  a  2-inch  bed  of  sand.  Cover  the  top  of  the  air  duct  with 
(2^)  inch  flagstone  with  joints  neatly  fitted  and  the  edges  cut  true  and  square.  The 
flagging  to  be  furnished  by  (this)  contractor. 


SPECIFICATIONS.  381 

Fire  Walls. — This  contractor  shall  furnish  and  set,  in  Portland  cement,  salt- 
glazed  tile  copings  on  all  fire  walls  not  covered  by  stone  or  metal  copings.  The 
copings  are  to  be  2  inches  wider  than  the  walls  and  to  have  lapped  joints. 

Ventilators. — Leave  ventilating  openings  in  the  foundation  walls  and  between  roof 
and  ceiling  joist,  where  shown  on  drawings,  and  put  cast  iron  gratings  in  the  open- 
ings. 

Cutting  and  Fitting. — This  contractor  shall  do  promptly  and  at  the  time  the 
superintendent  so  directs,  all  cutting  and  fitting  that  may  be  required  in  connection, 
with  the  mason  work  by  other  contractors  to  make  their  work  come  right,  and  shall 
make  good  after  them. 

Setting  Iron-work. — This  contractor  is  to  set  all  iron  plates  resting  on  the  brick- 
work, and  all  steel  beams  supporting  brick  walls;  also  all  iron  lintels,  tie-rods  and 
skewbacks  used  in  connection  with  brick  arches  or  over  openings. 

All  such  work  will  be  furnished  at  the  sidewalk  by  another  contractor,  and  this 
contractor  shall  set  the  same  in  such  position  and  at  such  height  as  the  superintend- 
ent shall  direct.  All  plates  to  be  solidly  bedded,  true  and  level,  in  I  to  2  fresh 
(Atlas)  Portland  cement  mortar;  the  brickwork  to  be  brought  to  such  a  height  that 
the  bedding  joint  shall  not  exceed  \  inch. 

[Where  there  is  but  little  ironwork  it  is  sometimes  desirable  to 
specify  that  the  brick  mason  shall  assist  the  carpenter  in  setting  iron 
columns  and  steel  beams.  Large  contracts  for  iron  and  steel  work 
are  generally  erected  by  a  special  contractor.  All  ironwork  coming 
in  connection  with'  the  stonework  should  be  set  by  the  same  con- 
tractor that  sets  the  stonework.] 

Setting  Cut  Stone . — The  contractor  for  the  stonework  will  set  all  belt  courses, 
stone  arches,  coping,  steps  and  other  stone  where  fitting  may  be  required,  but  this 
contractor  shall  set  all  single  caps,  sills  and  bond  stones,  the  stone  being  delivered 
at  the  sidewalk.  All  such  pieces  of  stone  to  be  set  in  the  best  manner,  in  mortar  as 
specified  for  the  face  brick.  Sills  to  be  bedded  only  at  the  ends. 

Setting  Terra  Cotta. — This  contractor  shall  set  all  terra  cotta  work,  indicated  by 
pink  color  on  the  elevation  drawings,  in  the  best  manner,  in  the  same  kind  of  mor- 
tar as  is  specified  for  the  pressed  brickwork.  All  terra  cotta  work  that  does  not 
balance  on  the  wall,  or  where  indicated  on  the  drawings,  shall  be  securely  tied  to 
the  backing  by  wrought  iron  anchors,  of  approved  pattern,  thoroughly  bedded  in 
cement  mortar.  (See  also  specifications  for  terra  cotta  work.) 

Cleaning  Down  and  Pointing. — On  completion  of  the  brickwork  this  contractor 
is  to  thoroughly  clean  the  face  brick,  using  dilute  muriatic  acid  and  water,  applied 
with  a  scrubbing  brush.  Care  must  be  taken  not  to  let  the  acid  run  over  the  cut  stone. 
(Some  stones  are  injured  by  acid  and  must  be  cleaned  with  water  only.)  While 
cleaning  down  this  contractor  is  to  point  up  under  all  sills,  and  wherever  required  to 
leave  the  wall  in  perfect  condition. 

[Where  there  is  little  cut  stonework  the  cleaning  and  pointing  of 
it  may  also  be  included  in  this  specification.] 

Outhouses — [Customary  only  in  Western  cities.] — Build  the  outhouses  and  ash 
pit  on  the  rear  of  the  lot,  as  shown  by  plans,  of  hard-burned  brick.  Arch  over  the 
ash  pit  and  give  a  heavy  coat  of  (Portland)  cement  mortar.  Leave  an  opening  in 


382  BUILDING  CONSTRUCTION. 


< 


the  top  for  putting  in  ashes  and  provide  an  iron  ring  and  cover  for  same.  Furnish 
and  set  on  the  alley  side  at  the  grade  a  cast  iron  ash  pit  door  and  frame. 

Rubbish. — Clean  out  all  boards,  plank,  mortar,  brick  and  other  rubbish  caused 
by  the  brick  masons,  and  remove  from  the  building  and  grounds,  on  completion  of 
the  brickwork  or  when  directed  by  the  superintendent.* 

Brick  Paving  (for  yards.) — Pave  the  yards  and  areas  where  so  indicated  on  plans 
with  good  hard  (vitrified)  paving  bricks,  sound  and  square,  laid  flat,  herring-bone 
fashion,  on  a  bed  of  sand  from  (4)  to  (6)  inches  deep. 

[The  necessary  depth  of  sand  varies  with  the  quality  of  the  soil,  a 
stiff  clay  requiring  the  most  sand  ;  on  such  soils  a  bed  of  furnace 
cinders,  etc.,  may  be  used  to  advantage  before  the  sand  is  put  down.] 

After  the  bricks  are  laid  and  graded  (which  should  be  about  I  inch  in  10  feet)  to 
drain  the  water  to  the  grade  or  to  its  proper  outlet,  the  entire  surface  must  be  cov- 
ered with  sand,  which  must  be  swept  over  the  bricks  until  the  joints  are  thoroughly 
filled. 

[For  a  better  pavement  the  joints  should  be  grouted  in  liquid 
cement  mortar  and  the  sand  spread  over  afterward.  Where  extra 
thickness  of  wearing  surface  is  required  the  bricks  may  be  laid  on 
edge  and  grouted  or  covered  with  sand  as  above.] 

Where  brick  gutters  are  shown  the  bricks  are  to  be  laid  lengthways  and  the  joints 
grouted  in  cement  mortar. 

(For  requirements  for  paving  brick  for  streets  and  driveways,  see  Section  226.) 

SPECIFICATIONS  FOR  LAYING  MASONRY  IN  FREEZING 
WEATHER.f 

382. — Only  in  case  of  absolute  necessity  shall  any  masonry  be  laid  in  freezing 
weather.  (See  Sections  139  and  239.) 

Any  masonry  laid  in  freezing  weather  must  not  be  pointed  until  warm  weather  in 
the  spring.  If  necessary,  masonry  may  be  laid  in  freezing  weather,  provided  the 
stone  or  brick  are  warmed  sufficiently  to  remove  ice  from  the  suface  and  the  mortar 
is  mixed  with  brine  made  as  follows:  Dissolve  I  pound  of  salt  in  18  gallons  of  water 
when  the  temperature  is  at  32°  F.,  and  add  i  ounce  of  salt  for  every  degree  the  tem- 
perature is  below  30°  F.,  or  enough  salt,  whatever  the  temperature,  to  prevent  the 
mortar  freezing. 

SPECIFICATIONS  FOR  FIREPROOFING.J 
(HOLLOW  TILE  SYSTEM.) 

383- — The  following  specifications  are  intended  to  include  the  fireproofing  of  all 
the  steel  in  the  building,  the  filling  in  between  the  beams  forming  floors  and  roof, 
and  the  concreting  over  the  same  to  the  top  of  the  floor  strips.  Also  the  covering  of 

*  If  in  the  general  conditions  this  paragraph  may  be  omitted. 
t  Baker's  Treatise  on  Masonry  Construction. 

$  Modeled  after  the  specification  for  the  Fort  Dearborn  Building,  Chicago;  Messrs.  Jenney  & 
Mundie,  architects. 


SPECIFIC  A  TIONS.  383 

all  columns,  both  those  standing  clear  and  those  partly  incased  in  the  walls.  Alsa 
the  building  of  all  tile  partitions  and  tile  vaults,  and  the  walls  of  pent  houses  on  the 
roof. 

This  contractor  shall  furnish  all  material,  including  the  mortar  for  setting 
the  same,  and  shall  do  all  his  own  hoisting  and  set  all  the  work  in  a  thorough, 
substantial  and  workmanlike  manner,  to  the  satisfaction  of  the  superintendent. 

Mortar. — All  work  shall  be  laid  in  mortar  composed  of  3  parts  of  best  fresh  lime 
mortar  and  I  part  best  (Louisville)  cement,  thoroughly  mixed  together  just  before 
using.  Said  lime  mortar  shall  be  composed  of  fresh-burned  lime  and  clean,  sharp 
sand  in  proportions  best  suited  to  this  work.  (For  partitions  Acme  cement  plaster 
may  be  used.  See  Section  344.) 

Floors. — All  floors  shall  be  constructed  of  flat  arches  (of  porous  or  semi- porous- 
tile,  end-method  construction*)  set  in  between  the  beams  and  of  a  shape  that  will 
give  a  uniform  flabceiling  in  the  rooms  below.  The  bottoms  and  projections  of  all! 
beams  and  girders  must  be  protected  by  projecting  parts  of  tile  or  by  separate  beam 
slabs.  In  laying  the  floor  arches  every  floor  joint  shall  be  filled  full  over  its  entire 
surface  from  top  to  bottom.  No  joints  to  exceed  ^  inch  in  thickness. 

No  clipped  or  broken  tiles  will  be  allowed  in  the  arches,  and  no  cutting  of  arches 
will  be  permitted  except  where  absolutely  necessary  and  under  the  approval  of  the 
superintendent.  All  the  arches  must  be  formed  to  fit  the  various  spans  between  floor 
beams,  and  in  all  cases  special  patterns  of  voussoirs  or  keys  must  be  moulded  and  set 
where  it  is  impossible  to  set  the  regular  form. 

All  floor  arches,  ten  days  after  they  are  laid,  and  before  they  are  concreted,  shall 
be  subject  to  a  test  of  a  roller,  15  inches  face,  and  loaded  so  as  to  weigh  1,500 
pounds,  rolled  over  them  in  any  direction. 

[This  test  is  only  intended  to  provide  against  poor  workmanship 
and  improper  setting  of  the  tile.  If  any  system  whose  strength  has 
not  been  fully  demonstrated  is  to  be  used,  it  should  be  subjected  to 
a  more  severe  test.  See  Section  299.] 

Columns. — All  columns  shall  be  covered  with  (porous)  column  tile  held  by  metal 
clamps,  both  in  horizontal  and  vertical  joints.  These  column  protections  shall  be  so 
made  as  to  conform  with  the  city  ordinance. 

[Where  the  city  ordinance  is  not  sufficiently  strict  on  this  point, 
the  specifications  should  be  more  definite  as  to  the  shape  of  the  tile. 
See  Section  318.] 

Roof. — The  roof  shall  be  constructed  in  the  same  way  as  the  floors,  except  that  the 
top  of  the  tile  shall  be  flush  with  the  beams  and  the  soffits  may  be  segmental,  with 
raised  skewbacks. 

Partitions. — Build  all  partitions  shown  on  the  several  plans  of  (porous,  semi- 
porous  or  dense)  hollow  tile,  4  inches  thick  in  the  first  and  second  stories  and  3. 
inches  thick  in  all  other  stories  except  the  hall  partitions,  which  are  to  be  4 
inches  thick  throughout  the  building. 

In  glazed  partitions  the  lower  parts  and  all  parts  other  than  the  sash  and  frames, 
shall  be  of  tile. 

*  This  clause  is  not  in  the  Fort  Dearborn  specification. 


384  BUILDING  CONSTRUCTION. 

The  tiles  shall  be  set  breaking  joints  and  to  be  tied  with  metal  ties  or  clamps. 

Furring  for  false  Beams  and  Cornices. — This  contractor  is  also  to  furnish  and 
put  in  place  tile  furring  for  the  cornice  and  false  beams  in  the  (bank  and  assembly 
hall),  to  be  of  profiles  and  sections  as  shown  by  drawings.  (See  Section  349.) 

The  cove  and  ceiling  pieces  of  the  cornice,  and  all  parts  of  the  beams,  to  have 
holes  cast  for  bolts,  spaced  not  over  12  inches  apart  and  at  least  two  bolts  for  each 
piece.  The  furring  to  be  properly  and  securely  mitred  at  angles  and  all  to  be  prop- 
erly bedded,  with  close  joints,  in  mortar  as  specified  above. 

All  suspended  pieces  to  be  substantially  fastened  in  place  by^-inch  diameter 
T-head  bolts,  spaced  not  over  12  inches  apart,  with  nuts  and  washers  to  each. 

(Or,  all  furring  for  cornices  and  false  beams  will  be  put  up  by  the  contractor  for 
plastering.) 

Wall  Furring. — Fur  the  outside  walls  in  finished  portions  of  basement  with 
3-inch  (porous,  semi-porous  or  dense)  tile  so  as  to  form  a  vertical  and  true  surface  for 
tiling.  The  tiles  to  be  set  with  the  hollow  spaces  vertical,  and  to  be  securely  fas- 
tened to  the  wall  by  flat-headed  spikes. 

Miscellaneous. — All  tile  work  shall  be  straight  and  true. 

All  tiles  of  every  kind  must  be  thoroughly  burned  and  free  from  serious  cracks  or 
checks,  or  other  damages,  and  shall  be  laid  in  a  proper  and  workmanlike  manner. 

No  centres  to  be  lowered  until  the  mortar  has  set  hard. 

All  structural  steel  on  which  the  strength  of  the  building  depends  in  any  way, 
including  wind  bracing,  shall  be  protected  by  fireproof  covering  of  approved  shape 
and  substantially  fixed  in  place. 

All  tilework  to  be  left  in  suitable  condition  for  plastering. 

Concreting. — This  contractor  shall  fill  in  on  top  of  the  floor  arches  with  con- 
crete composed  of  i  part  (natural)  cement  mortar  and  4  parts  of  screened  boiler 
cinders,  to  be  leveled  off  at  the  top  of  the  highest  beams  or  girders,  and  after  the 
floor  strips  are  set  by  the  carpenter  to  be  filled  in  between  said  strips  with  the  same 
•concrete  pressed  down  hard  with  a  reasonably  true  surface  \  inch  below  the  top  of 
the  strips. 

All  damage  to  tile  work  to  be  repaired  before  the  concrete  is  laid. 

Roof. — This  contractor  shall  cover  the  surface  of  the  roof  tiles  with  I  to  3  (nat- 
ural) cement  mortar  of  sufficient  thickness  to  come  f  inch  above  the  top  flanges  of 
beams  and  girders,  and  to  give  the  desired  pitch  to  the  roof,  with  a  reasonably  uniform 
surface. 

[If  the  tops  of  the  tiles  are  more  than  f  inch  below  the  tops  of  the 
girders,  concrete  may  be  used  for  filling  to  top  of  girders  and  £  inch 
of  mortar  applied  above.] 

Outside  Walls. — The  outside  walls  of  pent  house  on  roof  to  be  built  of  (4-inch) 
hard-burnt  wall  tile,  clamped  together,  and  set  in  mortar  as  above  specified.  Every 
joint,  both  vertical  and  horizontal,  to  be  thoroughly  filled  over  its  entire  surface  with 
mortar,  and  all  outside  joints  to  be  struck  in  a  neat  and  workmanlike  manner. 

This  contractor  shall  give  a  written  guarantee  that  the  outside  face  of  these  tile 
will  stand  the  weather  for  (five)  years  dating  from  the  completion  of  the  wall,  and 
agree  to  replace  any  tile  injured  by  the  weather,  either  in  winter  or  summer  during 
said  period,  promptly  and  at  his  own.expense. 


SPECIFIC  A  TIONS.  385 

SPECIFICATIONS  FOR  TERRA  COTTA  TRIMMINGS.* 

384. — Material. — This  contractor  shall  furnish  and  set  wherever  called  for  on 
drawings  terra  cotta  to  exactly  match  in  color  the  sample  submitted,  all  in  strict 
accordance  with  detail  drawings.  Material  for  all  terra  cotta  to  be  carefully  selected 
clay,  left  in  perfect  condition  after  burning,  and  uniform  in  color.  All  pieces  to  be 
perfectly  straight  and  true,  and  with  mould  of  uniform  size  where  continuous.  No 
warped  or  discolored  pieces  will  be  allowed.  This  contractor  to  furnish  a  sufficient 
number  of  over  pieces,  so  as  to  avoid  all  delay. 

Modeling. — All  work  shall  be  carefully  modeled  by  skilled  workmen,  in  strict 
accordance  with  detail  drawings,  and  models  shall  be  submitted  for  architect's 
approval  before  the  work  is  burned.  No  work  burnt  without  such  approval  will  be 
accepted  by  the  architects  unless  perfectly  satisfactory. 

Mortar. — All  mortar  used  for  exposed  joints  in  terra  cotta  work  shall  be  composed 
of  lime  putty,  colored  with  (Pecora)  or  (Peerless)  mortar  stains  to  match  the  mortar 
used  for  pressed  brickwork. 

Ornamental  Fronts,  Belt  Courses,  Bands. — This  contractor  shall  furnish  and  set 
all  ornamental  terra  cotta,  belt  courses  and  bands,  as  shown  on  elevations  or  sections 
or  where  otherwise  indicated,  in  strict  accordance  with  detail  drawings.  All  terra 
cotta  work  to  be  secured  to  the  ironwork  in  the  most  approved  manner,  with  sub- 
stantial wrought  iron  or  copper  anchors,  and  thoroughly  bedded  in  cement  mortar. 
All  horizontal  joints  to  have  lap  joints.  All  projecting  courses  to  have  drips  formed 
on  under  side. 

Caps  and  Jambs,  Sills. — All  caps  and  jambs  where  indicated  as  terra  cotta  will 
be  constructed  in  strict  accordance  with  detail  drawings.  All  sills  and  belt  courses 
to  have  countersunk  cement  joints  as  directed  by  the  superintendent.  All  projecting 
sills  to  have  drips  formed  on  under  side  and  all  sills  shall  be  raggled  for  hoop  iron, 
which  shall  be  bedded  by  this  contractor  in  cement  mortar. 

Terra  Cotta  Mzillions. — All  ornamental  mullions  of  terra  cotta  to  be  secured  to 
metal  uprights  in  approved  manner,  and  well  bedded  and  slushed  with  cement 
moitar. 

Cornice, — This  contractor  shall  construct  the  cornice  in  strict  accordance  with  detail 
drawings,  with  sufficient  projection  through  walls  and  approved  anchorage  to  the 
metal  work  to  make  them  thoroughly  secure.  This  contractor  to  furnish  all  neces- 
sary anchors.  Form  raggle  in  cornice  as  shown  for  connection  of  gutter,  this  raggle 
to  be  on  face  of  terra  cotta.  Leave  openings  in  cornice  for  down-spouts  as  shown. 

Anchors. — This  contractor  shall  furnish  all  anchors  of  substantial  wrought  iron  or 
copper,  for  the  proper  support  and  anchoring  of  all  terra  cotta  used  in  his  work.  All 
terra  cotta  to  be  drawn  to  tight  and  accurate  joints  to  entire  satisfaction  of  the  super- 
intendent. All  terra  cotta  must  fit  the  supporting  metal  work  exactly. 

Cutting  and  Fitting. — This  contractor  shall  do  all  fitting  necessary  to  make  his 
work  perfect  in  every  particular,  all  possible  cutting  and  fitting  to  be  done  at  the 
factory  before  delivery. 

Protection  of  Terra  Cotta. — All  projecting  terra  cotta  shall  be  protected  with 
sound  plank  during  erection  of  the  building  by  terra  cotta  contractor,  said  protection 
pieces  to  be  removed  on  cleaning  down  the  building. 

*  From  specifications  of  Fort  Dearborn  Building. 


386  BUILDING  CONSTRUCTION, 

Cleaning  Down. — This  contractor  shall  carefully  clea»  down  all  terra  cotta  work 
on  completion  of  building,  when  directed  by  the  superintendent,  and  shall  carefully 
point  up  all  joints  before  leaving  the  work. 

SPECIFICATIONS  FOR  LATHING  AND  PLASTERING. 

(ORDINARY  WORK.) 

385. — Lathing.— Lath  all  (walls)  partitions,  ceilings,  and  all  furring,  studding, 
under  side  of  stairs,  etc.,  with  best  quality  of  pine  (spruce)  lath,  free  from  sap,  bark 
or  dead  knots,  and  of  full  thickness.  To  be  laid  f  inch  apart  on  the  ceilings  and  -J- 
inch  or  more  on  the  walls,  with  four  (five)  nailings  to  the  lath  and  joints  broken  every 
1 8  inches;  all  to  be  put  on  horizontally.  Under  no  circumstances  must  laths  stop 
and  form  a  long,  straight  vertical  joint,  nor  any  lath  be  put  on  vertically  to  finish  out 
to  angles  or  corners;  neither  shall  any  lath  run  through  angles  and  behind  studding 
from  one  room  to  another.  All  corners  must  be  made  solid  before  lathing.  Should 
the  lathers  find  any  angles  not  made  solid,  or  any  furring  or  studding  not  properly 
secured,  they  are  to  stop  and  notify  the  carpenter  to  make  permanent  the  same. 

Metal  Lathing. — Lath  walls  or  partitions  in  front  of  hot-air  pipes  with  metal 
lathing  approved  by  the  architect.  Cover  all  recesses  in  brick  walls  that  are  to  be 
plastered,  all  wood  lintels  and  wherever  woodwork  joins  the  brick  walls  (if  latter  are 
not  furred)  with  (Bostwick)  or  expanded  metal  lathing  properly  put  up  and  secured. 

Plastering — Back-Plastering  (for  frame  buildings). — Back-plaster  the  whole  of 
the  exterior  walls  from  sill  to  plate  between  the  studs,  also  between  the  rafters  of 
finished  portion  of  attic,  on  laths  nailed  horizontally,  ^  inch  apart,  to  other  laths  or 
vertical  strips  put  on  the  inside  of  the  boarding,  with  one  heavy  coat  of  lime  and  hair 
mortar,  well  troweled  and  made  tight  against  the  studs,  girts,  plates  and  rafters. 

One-Coat  Work. — Plaster  the  (basement  ceiling)  one  heavy  coat  of  rich  lime  and 
hair  mortar,  well  troweled  and  smoothed. 

Three-Coat  Work. — All  other  walls,  partitions,  ceilings  and  soffits  throughout  the 
building  to  be  plastered  three  coats  in  the  best  manner. 

The  first  or  scratch  coat  to  be  made  of  first  quality  (Rockland)  lump  lime,  clean, 
sharp  bank  (river)  sand,  free  from  loam  and  salt,  and  best  quality  clean,  long  cattle 
hair,  mixed  in  the  proportion  of  sj-  barrels  of  sand  and  ij  bushels  of  hair  to  each 
cask  or  each  200  pounds  of  lump  lime.  To  be  thoroughly  mixed  by  continued  work- 
ing and  stacked  in  the  rough  for  at  least  (7)  days  before  putting  on.  The  hair  and 
sand  are  not  to  be  mixed  with  the  lime  until  the  lime  has  been  slaked  at  least  six 
hours. 

The  scratch  coat  to  be  properly  put  on  and  applied  with  sufficient  force  to  give  a 
good  clinch,  and  to  be  well  scratched  and  allowed  to  dry  before  the  brown  coat  is 
put  on. 

The  second  or  brown  coat  to  be  mixed  same  as  the  scratch  coat  (except  that  6J 
barrels  of  sand  and  but  \  bushel  of  hair  to  i  of  lime  may  be  used).  Level  and  float 
up  the  brown  coat  and  make  it  true  at  all  points. 

White  Coat. — The  third  coat  (except  in  the  halls  and  dining  room)  to  be  mixed 
with  lime  putty,  plaster  of  Paris  and  marble  dust  (or  lime  putty  and  King's  Superfine 
Windsor  Cement),  thoroughly  troweled  and  brushed  to  a  hard,  smooth  surface. 

Sand  Finish. — The  third  coat  in  halls  and  dining  room  to  be  composed  of  lime 
putty  and  clean-washed  (beach)  sand,  floated  with  a  wooden  or  cork-faced  float  to  an 
even  surface,  equal  to  No.  I  sandpaper. 


SPECIFICATIONS.  387 

All  lathing  and  plastering  to  extend  clear  down  to  the  floor  ;  all  walls  to  be  straight 
and  plumb  and  even  with  grounds  ;  all  angles  to  be  maintained  sharp  and  regular  in 
form. 

Plaster  Cornices,  etc. — Run  all  around  the  (parlor)  a  plaster  stucco  cornice,  to 
extend  (8)  inches  on  the  ceiling  and  (6)  inches  on  the  wall,  and  to  be  run  in  strict 
accordance  with  detail  drawing.  Run  all  beads,  quirks,  etc.,  to  angles  of  beam 
soffits  as  indicated  on  drawings,  and  finish  at  each  end  of  beams  with  cast  plaster 
brackets,  modeled  according  to  the  architect's  full-size  detail. 

Put  up  cast  plaster  centrepieces  in  (3)  rooms,  for  which  allow  the  sum  of  ($25),  the 
same  to  be  expended  under  the  direction  of  the  architect. 

The  plasterer  must  clear  out  all  boards,  planks,  horses,  mortar,  dirt  and  all  loose 
rubbish  made  by  him  or  his  men,  and  remove  from  the  rooms  and  premises,  as  fast 
as  the  several  stories  are  plastered,  and  leave  the  floors  broom  clean.  Patch  up  and 
repair  the  plastering  after  the  carpenters  and  other  mechanics  in  a  skillful  manner 
and  leave  the  work  perfect  on  completion. 

Two-Coat  Work. — The  following  is  the  usual  form  of  specification  for  house 
work  in  New  England  : 

All  walls,  ceilings,  soffits  and  partitions  throughout  the  (first  and  second  stories 
and  attic)  to  be  plastered  two  coats  in  the  very  best  manner. 

"  The  first  coat  to  be  of  best  quality  (Rockland)  lime  and  clean,  sharp  sand,  well 
mixed  with  i^  bushels  of  best  long  cattle  hair  to  each  cask  of  lime;  to  be  thoroughly 
worked  and  stacked  at  least  one  week  before  using  in  some  sheltered  place,  but  not 
in  the  cellar  of  the  house  ;  all  to  be  well  troweled,  straightened  with  a  straight-edge 
and  made  perfectly  true  and  brought  well  up  to  the  grounds. 

"The  second  or  'skim'  coat  to  be  of  best  (Rockland)  lime  putty  and  washed 
(beach)  sand,  troweled  to  a  hard,  smooth  surface." 

SPECIFICATIONS  FOR  HARD  PLASTERING. 

386. — All  walls,  ceilings,  soffits  and  partitions  throughout  the  building  to  be 
plastered  three  coats,  in  the  best  manner,  as  specified  below. 

The  first  and  second  coats  to  be  of  (Acme)  cement  plaster  or  dry  mortar — the 
first  coat  on  lath  work  to  be  fibred  material. 

The  material  to  be  mixed  with  clean  water  to  the  proper  consistency  and  applied 
in  the  usual  way.  The  first  coat  to  be  scratched  or  broomed  to  form  a  rough  surface 
for  brown  coat.  Apply  the  brown  coat  as  soon  as  the  scratch  coat  is  two-thirds  dry 
or  has  set  sufficiently  to  receive  it,  bringing  the  mortar  out  even  with  the  grounds 
and  to  a  true  surface.  Scratch  roughly  for  all  stucco  cornices  and  mouldings. 

Sand  Finish. — After  the  brown  coat  has  been  on  twenty-four  hours  finish  the 
walls  and  ceiling  of  (hall  and  vestibules)  with  (Windsor)  sand  finish,  mixed  with  clean 
water  only  and  floated  to  a  true  surface  with  clear  soft  pine  or  cork-faced  floats. 

[Or  lime  putty  and  sand  may  be  used  as  in  ordinary  plastering.] 
Hard  Finish. — When  the  browning  is  two-thirds  dry,  finish  all  other  walls  and 
ceilings  throughout  the  building  with  a  white  coat  made  of  equal  parts  of  lime  putty 
and  plaster  of  Paris,  troweled  and  brushed  to  a  hard  and  uniform  surface. 

[For  a  better  grade  of  finish  add  a  quart  of  marble  dust  to  each 

batch  of  plaster,  or  use  Windsor  cement  instead  of  plaster  of  Paris.] 

All  brick  and  tile  walls  and  all  wood  laths  to  be  well  wet  just  before  plastering. 


388  BUILDING  CONSTRUCTION. 

Only  as  much  mortar  as  can  be  used  within  one  hour  is  to  be  mixed  at  one  time, 
and  under  no  circumstances  shall  any  mortar  that  has  commenced  to  set  be  retem- 
pered.  , 

The  plasterer  must  strictly  observe  and  follow  the  directions  accompanying  the 
plaster. 

[Specify  for  patching,  cornices,  etc.,  as  in  Section  385.] 

SPECIFICATIONS  FOR  WIRE  LATHING  WITH  METAL 
FURRING. 

(OVER  WOODWORK.) 

This  contractor  is  to  fur  all  ceilings,  soffits  of  stairs,  all  timber  beams  and 
posts,  and  both  sides  of  all  wood  partitions  throughout  the  building  with  Ham- 
mond's metal  furring  with  (i)-inch  bearings,  the  stiffening  rods  to  be  placed  (6) 
(see  Section  333)  inches  on  centres,  across  floor  beams  and  studding,  and  a  line  of 
furring  to  be  placed  on  each  side  of  each  angle,  as  near  the  angle  as  possible. 
Posts  and  girders  to  be  furred  lengthways,  with  a  line  on  each  angle,  and  every  7^ 
inches  between. 

[If  the  architect  does  not  wish  to  specify  this  furring  he  can  specify 
-^x-|-inch  corrugated  band  iron,  put  up  with  if -inch  staples.] 

All  furring  to  be  substantially  secured  with  2-inch  No.  13  steel  staples  (see 
Section  333)  and  to  be  set  to  give  a  true  and  even  surface  for  the  lathing. 

Cover  all  the  above  surfaces  with  (plain,  painted,  japanned,  galvanized)  wire 
lathing  (2|)  (2^x5)  mesh,  No.  (20)  wire,  tightly  stretched  and  secured  with  (a)-inch 
No.  13  steel  staples  (see  Section  333)  driven  over  the  lath  and  furring  at  each  bear- 
ing where  the  lathing  runs  crossways  of  the  timbers,  and  every  (6)  inches  where  the 
bearings  run  parallel  with  the  timbers.  The  lathing  to  be  lapped  at  least  {  inch 
where  the  strips  come  together  and  i^  or  2  inches  at  all  angles  of  walls  or  wall  and 
ceiling. 

SPECIFICATIONS  FOR  STIFFENED  WIRE  LATHING. 
(OVER  WOOD  AND  BRICKWORK.) 

Cover  all  ceilings,  soffits  of  stairs,  both  sides  of  all  wood  partitions,  and  all 
wooden  posts  and  girders  throughout  the  building  with  the  (Roebling)  stiffened 
wire  lath,  painted.  No.  20  gauge,  and  (2^x5)  (2^x2^)  mesh,  with  f-inch  V-ribs. 
(For  the  posts  and  girders  and  on  planking  f-inch  ribs  will  give  better  protection 
both  from  fire  and  dry  rot.) 

The  lathing  to  be  applied  with  the  ribs  running  at  right  angles  to  the  beams;  to 
be  tightly  stretched  and  secured  with  galvanized  steel  nails,  driven  through  each 
end  of  each  rib,  and  at  every  bearing  between  and  every  9  inches  on  timbers  and 
planking.  The  strips  to  lap  on  a  joist  in  every  case  and  to  be  carried  down  2 
inches  on  the  walls.  Care  must  be  exercised  to  see  that  no  holes  are  left  at  any 
place  in  the  ceiling  where  the  plastering  can  drop  off  and  fire  enter. 

Lath  the  outside  walls  of  finished  portion  of  basement,  from  floor  to  ceiling,  with 
(Roebling)  stiffened  lathing,  painted,  No.  20  gauge,  (2^x5)  mesh  and  i^-inch  V-ribs. 
To  be  tightly  stretched,  lapped  i  inch  and  secured  to  the  walls  with  rod.  steel 
nails  driven  through  the  ribs  every  8j  inches  and  at  each  end.  The  lathing  to  be 
applied  with  the  stiffening  bars  vertical.  All  the  above  lathing  to  be  done  in  the 
most  approved  manner  so  as  to  give  a  firm  surface  upon  which  to  apply  the  plaster. 


SPECIFICATIONS.  389 

SPECIFICATIONS  FOR  METAL  LATH  ON  IRONWORK, 

This  contractor  is  to  furnish  and  put  up  in  a  substantial  manner  all  iron  furring 
and  lathing  for  enclosing  the  posts  and  girders  and  for  forming  the  cornices,  as 
shown  on  the  drawings  and  as  specified  below.  The  lathing  to  be  well  lapped  on- 
to walls  and  ceilings  to  make  a  tight  job. 

Girders. — All  girders  projecting  below  the  level  of  ceilings  shall  be  encased  by 
•wire  lathing,  stiffened  with  a  ^-inch  solid  rib.  The  lathing  to  be  rigidly  supported 
by  light  iron  furring  built  out  to  correct  outline  as  shown  on  the  plans.  The  fur- 
ring to  be  so  designed  that  the  weight  of  the  plaster  and  falsework  will  be  supported 
by  the  girder  and  so  as  to  afford  a  firm  surface  for  plastering. 

Cornices. — Full-size  details  of  all  cornice  work  will  be  supplied  by  the  architects 
at  the  proper  time.  Iron  brackets,  bent  to  correct  outline  and  spaced  not  more 
than  1 8  inches  apart,  shall  be  secured  in  position  in  the  best  manner  and  well 
braced.  Over  this  falsework  wire  lathing,  stiffened  with  a  ^-inch  steel  rib,  shall  be 
laced  so  as  to  conform  with  the  profile  of  the  brackets  and  produce  a  smooth,  firm 
surface  for  plastering. 

Columns. — All  columns  not  enclosed  in  brickwork  are  to  be  wire  lathed.  Suit- 
able light  iron  furring  shall  be  provided  so  as  to  offset  the  lathing  at  least  2  inches 
from  the  ironwork  and  finish  round  or  square  as  shown  on  the  plans.  The  lath- 
ing to  be  stiffened  with  a  -J-inch  solid  rib  woven  in  every  7*  inches. 

All  other  exposed  iron-work  shall  be  suitably  encased  with  wire  lathing  supported 
whenever  necessary  by  light  iron  furring,  and  in  all  cases  providing  an  air  space  of 
at  least  i  inch  between  the  ironwork  and  the  plaster. 

All  the  above  lathing  to  be  painted  (galvanized),  of  No.  20  gauge  and  (2^x5) 
mesh,  and  to  be  securely  laced  to  the  furring  with  No.  19  galvanized  lacing  wire. 

(All  work  here  contemplated  must  comply  with  the  requirements  of  the  Depart- 
ment of  Building.) 

SOLID  PARTITIONS. 

(METAL  LATH  AND  STUDDING.) 

This  contractor  is  to  provide  all  metal  work,  and  erect  the  partitions  indicated  by 
(gray)  color  or  otherwise  marked  on  the  plans,  and  leave  them  in  perfect  condition 
for  the  plasterer.  \Vood  furring  will  be  furnished  in  pieces  of  the  proper  size  by 
the  carpenter,  but  this  contractor  is  to  secure  them  to  the  metal  work.  The  above 
partitions  to  be  formed  of  studs  of  f  x^-inch  channel  iron,  placed  16  inches  centre 
to  centre  for  partitions  (n)  feet  high  or  less  and  12  inches  centre  to  centre  for  par- 
titions more  than  (n)  feet  in  height.  All  openings  to  be  framed  with  ixi-inch  by 
j35-inch  angle  irons. 

Studs  must  be  securely  fastened  at  top  and  bottom,  and  grounds  for  door  and 
window  openings  must  be  firmly  secured  to  the  studs.  Grounds  for  nailing  of  base, 
chair  rail,  picture  moulds,  etc.,  must  be  fitted  and  fastened  in  true  and  straight,  \ 
inch  over  the  line  of  studs  on  face  side  of  partition  and  \  inch  over  line  of  studs  on 
reverse  side,  i^  inches  total  thickness. 

2.  After  grounds  are  put  on  the  face  side  of  partition  to  be  covered  with  (Bost- 
•wick  steel  lath  put  on  with  the  loops  inward  or  between  the  studs);  the  sheets  of 
lath  must  come  close  together  or  lap  on  horizontal  joints  and  the  vertical  joints  must 
be  broken  properly  ;  the  lath  must  be  secured  by  naiiing'on  with  trunk  nails,  driven. 


39o  BUILDING  CONSTRUCTION. 

through  alongside  of  stud  and  clinched  around  behind  it,  each  nail  being  on  opposite 
side  of  sfid  from  the  one  above  and  below  it.  The  metal  work  must  be  properly 
braced  to  hold  it  in  position  until  the  mortar  has  become  firm. 

(The  bracing  should  be  a  straight-edged  flooring  board  put  on  over  the  lath,  and 
staples  set  around  the  studs  driven  into  the  board  can  be  easily  drawn  afterward, 
leaving  only  i  inch  of  strip  to  fill  in  on  face  of  partition  and  the  staple  holes  on 
reverse  after  partitions  become  rigid.) 

[For  wire  lathing  specify  as  follows  instead  of  as  in  paragraph  2.] 

3.  After  grounds  are  put  on  cover  one  side  of  the  partition  with  No.  20  painted 

(2|.\5)  mesh  wire  lathing,  stiffened  with  a  {-inch  solid  steel  rib  woven  in  at  intervals 

of  ~i\  inches,  the  rods  to  run  crossways  of  the  studs.      The  lathing  to  be  firmly 

secured  to  the  studding  by  No.  19  galvanized  lacing  wire. 

SPECIFICATIONS  FOR  THE  "ROEBLING    FIREPROOF 
FLOOR." 

[This  specification  is  given  as  a  guide  in  preparing  specifications 
for  this  and  similar  floors.  Most  of  the  various  fireproofing  compa- 
nies have  printed  specifications  for  their  systems,  which  they  furnish 
to  architects  on  application.] 

The  floor  construction  to  be  used  in  this  building  shall  be  that  kncwn  as  the 
"  Roebling  System,"  consisting  of  a  steel-ribbed  wire  cloth  and  concrete  arch  with 
ceilings  suspended  below  the  level  of  the  floor  beams.  A  continuous  air  space 
between  the  floor  and  ceiling  and  around  the  girders  shall  be  provided. 

The  wire  centring  for  the  floors  shall  consist  of  No.  19,  four-warp  two-filling 
•wire  cloth  stiffened  with  f  to  J-inch  steel  rods  woven  into  the  cloth  at  intervals  of 
about  9  inches.  This  centring  shall  be  sprung  in  between  the  I-beams  in  the 
form  of  an  arch  with  the  ends  of  the  rods  abutting  against  the  beams.  The  sheets 
to  be  well  lapped  and  securely  laced.  Over  the  crown  of  this  centring  one  or 
more  yKj-inch  steel  rods  shall  be  laced  parallel  to  the  beams  to  secure  proper  longi- 
tudinal bracing. 

In  all  spans  over  3  feet  6  inches  a  heavy  galvanized  wire  shall  be  dropped  down 
from  the  stiffening  rib  of  the  arch  at  intervals  of  not  over  3  feet  to  support  the 
ceiling. 

Over  the  wire  arch  so  constructed  cinder  concrete  mixed  in  the  proportions  of  I 
part  of  high-grade  Portland  cement  to  2  parts  of  sharp  sand  and  5  parts  of  clean 
cinder  shall  be  laid  to  a  sufficient  thickness  to  secure  the  required  strength,  as  des- 
ignated elsewhere  in  these  specifications.  The  concrete  generally  to  be  leveled 
(2  inches  above)  the  top  of  the  floor  beams  where  wood  floors  are  specified,  and  to 
the  specified  levels  where  other  than  wood  floors  are  designated. 

Every  alternate  nailing-sleeper  to  be  imbedded  in  concrete  so  as  to  form  a  fire 
stop.  These  sleepers  to  be  supplied  and  placed  in  position  over  the  beams  under 
the  carpenter's  contract. 

The  floors  to  be  subject  to  test  at  any  point  that  may  be  designated  by  the  archi- 
tect, and  at  any  time  after  the  concrete  is  fifteen  days  old.  The  floor  shall  in  all 
cases  develop  a  strength  of  1,000  pounds  per  square  foot  when  the  load  is  concen- 
trated, and  similarly  a  strength  of  600  pounds  per  square  foot  when  the  load  i» 
uniformly  distributed  over  one-half  of  the  span. 


APPENDIX. 


The  following  tables  relating  to  the  properties  and  chemical  composition 
«of  building  stones,  and  to  stone  buildings,  have  been  compiled  by  the 
-author  from  various  sources  (principally  from  several  volumes  of  Stone  and 
Merrill's  Stones  for  Building  and  Decoration),  and  are  believed  to  be 
reliable  : 

TABLE  A. 

SHOWING  THE  WEIGHT,  CRUSHING  STRENGTH  AND  RATIO  OF  ABSORPTION 
OF  VARIOUS  BUILDING  STONES. 


Kind  of  Stone. 

Locality. 

Approximate 
size  of  cube 
in  inches. 

Position. 

Strength  per 
square  inch. 

Weight  per 
cubic  foot. 

Ratio  of 
Absorption.  1 

Granite  (Biotite) 

2 

Bed 

15  698 

16 

Dix  Island    Me 

2 

15  ooo* 

166  5 

, 

2 

Bed 

14  425* 

166  9 

. 

2 

Edee 

14  937* 

166  9 

« 

Fox  Island    Me  

14  875* 

164.  i 

, 

Keene   N    H   . 

Bed 

10  375 

1  66 

i. 

Granite  (Hornblende) 

Bed 

12  423* 

Bed 

19  500* 

Rockport   Mass 

(  Bed 

16,300  ) 

i 

• 

Quincy,  Mass  

{Edge 

19-750) 

166.2 

168  7 

<«ranite  Biotite)  

Milford,  Conn  

6 

22,610 

Westerly,  R.  I  

2 

17,500 

165.6 

« 

2 

Edge 

14,937* 

166.9 

, 

2 

Bed 

18  125 

i 

< 

2 

Edge 

14  425 

IB- 

•Cranite  (Hornblende).  .  . 
-Granite  (Gabbro)  

East  Saint  Cloud,  Minn. 

Saint  Cloud,  Minn  
Duluth,  Minn  

2 

2 
2 

Bed 
Edge 
Bed 

£f 

28,000  ) 
26,250  ) 
16,000  | 
18,500  ) 
17  631 

168.2 

168.2 

175 

Granite  (Biotite)  

Tarrytown,  N.  Y  
Staten  Island,  N.  Y.  .  .  . 

2 
2 

Bed 
Bed 

i8,25of 

22,250-f 

162.2 

178.8 

.... 

,, 

2 

j  Bed 

12,976  ) 

006 

,( 

Platte  Canon,  Colo  

2 

Edge 
Bed 

15,594) 

14,585  / 

.006 

limestone  (Dolomite) 

Joliet   111  

2 

Edge 
Bed 

14,634  ) 
14  775* 

160 

i 

Lemont,  111  

2 

Bed 

12  OOO* 

165  3 

i 

Ximestone   Oolitic) 

Quincy,  111  
Bedford    Ind 

2 

Bed 

9,687* 

160.6 

TSV 

152   4 

1 

"      (buff) 

"Ijmestone  (Dolomite).  .  . 

Salem,  Ind  
Stillwater,  Minn  

2 
2 

(  Bed 

kr 

8.625 
25,000  ) 
25,000  ) 
10,750  ( 

144-3 
172.6 

160  4 

A 
**T 
JL 

/Edge 

12,750  J 

suddenly.        t  Cracked  before  bursting.        $  Tests  made  at  U.  S.  Arsenal,  Watertown,  Ma 


392 


BUILDING  CONSTRUCTION. 
TABLE  A.— {Continued.) 


Kind  of  Stone. 

Locality. 

Approximate 
size  of  cube 
in  inches. 

| 
1 

Strength  per 
square  inch. 

fj 

.M.H 

£3 

•  •  H-  i  Katio  °f 
J  J  **  1  Absorption. 

Limestone  (Dolomite).  .  . 
Limestone  (Magnesian).. 

Marble  (Dolomite)  

Red  Wing   Minn 

2 
2 
2 

6 
6  * 

2 

6 

J! 

Bed 
'  Edge 
Bed 
Edge 
Bed 
Edge 
Bed 

Edge 

23,000) 
23,250  $ 
",475* 
io.75u 
25,000* 
21,500 
22,900 
10,  746 
8,670 
10,976 
13,415 
ii  822 

162.2 
168.8 
171.9 

Glens  Falls,  N.  Y  

Lake  Champlain,  N.  Y. 

^ee,  Mass  
C  nitre  Rutland,  Vt  
Dorset.  Vt  
'Cherokee,"  Georgia... 

166.6 
167.8 

..  .. 

,i 

•i 

'Creole,"  Georgia  

6 

ti 

12,078 
11,420 
15  512 

« 

« 

4                  

'  Etowah,"  Georgia.  .  .  . 

6 

4  t 

10,642 

4  \ 

.... 

13,888 
8  354 

, 

, 

4  \ 

10  771 

Marble  (Pink)  
Marble  (White)  

East  Tennessee  

\ 

3  t 
a« 
»M 

4  t 
4  * 
6  * 
2  t 

2    t 
2 
2 
2 
6 
2 
2 
6 
2 

\ 

Bed 
Bed 

Ldf 

Bed 
Bed 
Bed 
Bed 
Bed 
Bed 
Bed 
Bed 
Bed 
Bed 

15,750 
17,212 
14,812 
13,750 
13,980 
13,330 
13,920 
15,020 
9,900 
12,250 

8,437 
14,085 
12,619 
18,401 
42,000 
17.250 
5.450 

6,212 
6,510 
8,222 

b,8oo 
12,810 
6,237 
11,505 
11,707 
10,514 

11,000 
6,000 

'.'.'.'.'.. 

I 

,, 

Marble  (Dark  Pink)  
Sandstone  (Brownstone). 

Sandstone  (Con.) 
'         Brown  (soft).. 
"       (hard). 
(Kibbe)  

,, 

,, 

,, 

„ 

Aver 
of  6t 

150.6 
133-7 
135-8 

age 
ests 

! 

East  Longmeadow,  Mass 
Potsdam,  N.  Y  

i              11 

Medina,  N.  Y  

(lilac  color).  .  . 
(light) 

North  Amherst,  Ohio  .  .  . 
Berea,  Ohio  

134 
140 

us's' 

149.3* 
140.7 
141.2 
140 

A 
*v 

i; 

.072 
.066 

'      

Hummelstown,  Pa  
Fond  du  Lac,  Wis  
Saint  Vrains,  Colo  
Fort  Collins,  Colo  
Stout,  Colo  

(hard,  red)... 
(hard,  gray).  . 

(light  red).  .  .  . 

Manitou,  Colo  

*  Burst  suddenly.  t  Cracked  before  bursting. 

$  Tests  made  at  U   S.  Arsenal,  Watertown,  Mass. 


APPENDIX. 


393 


TABLE  A.— {Continued.) 

SLATE. 


Locality. 

Modulus  of 
Rupture. 

Weight  per 
cubic  foot. 

Porosity. 

Corrodibility. 

Albion,  Penn  

7,150  Ibs 

*73  2 

o  238 

o  547 

Old  Bangor   Penn  

9,810    " 

*73  5 

o  145 

o  446 

Peach  bottom  region,  Penn  

11,260    " 

180.4 

0.224 

0.226 

TABLE  B. 

SHOWING  THE  CHEMICAL  COMPOSITION  OF  VARIOUS  BUILDING  STONES.* 
GRANITES. 


Description. 

Locality. 

| 

ffi 

Alumina. 

§| 

~O 

§ 

J 

Potash 
and  Soda. 

Light 

73  47 

15  07 

i   15 

4  48 

e    Q7 

Dark 

69  35 

18  83 

2  OO 

3  78 

Hornblende  

East  Saint  Cloud,  Minn. 

65.12 
74  43 

16.96 
12  68 

4.69 

3  82 

4-77 
I  28 

5.25 

3  88 

Duluth,  Minn  

5°  43 

23  83 

17  63 

4  79 

2    40 

Gabbro  

48  51 

13  79 

19  34 

8  34 

1.86 

SANDSTONES. 


Description. 

Locality. 

0 

33 

ci 

3 

<3 

« 

O  "O 

6 

3 

£j§ 

5 

Maynard  (red)  
Worcester  (red)  
Kibbe  quartz  
Brownstone  

E.  Longmeadow,  Mass.  . 
Portland,  Conn  

79-38 
88.89 
81.38 
69.94 
70.  ii 

8.75 
5.95 

9-44 
13-15 
13.49 

2.43 
1.79 

3-54 
2.48 
4  85 

2-57 
•  27 
.76 
3-09 

2    39 

2-79 
1.83 
4-49 

I.OI 

7  37+ 

Sandstone  

Stony  Point,  Mich  

84.57 

5.90 

6.48 

1.92 

Portage  Entry  (red)  . 
Quartzite             .... 

Lake  Superior,  Mich.  .  .  . 
Pipestone,  Minn  

94-73 

84.52 

0.36 
12  33 

2.64 

2    12 

0.69 

o  31 

•83 
2.31 

Buff            

Aniherst,  Ohio  

97  .00 

I  .OO 

1  .  15 

.  21 

Berea  

Berea,  Ohio  

96.90 

1.68 

•  55 

•  32 

Euclid  Bluestone..  . 
Columbia  

Euclid  County,  Ohio.  .  .  . 
Columbia,  Ohio  

95-00 
96.  50 

2.50 

1.  00 

1.50 
2.00 

Red 

I    IO 

I    92 

Elyria  
Sandstone  

Grafton,  Ohio  
Fond  du  Lac,  Minn.  .  .  . 

87.66 
78.24 
79  19 

1.72 
10.88 
3 

3-52 
3.83 

75 

-17 
-95 
7  76 

2.03 
3.26 

ii 

Dorchester.  N.  Brunsw'k 

82.^2 

7.O7 

l.e,S 

1.81 

T.6i 

*  Some  minor  elements  occurring  in  very  small  quantities  and  not  affecting  the  durability  of  the  stone 
are  omitted. 

f  Potash  and  soda. 


394 


BUILDING  CONSTRUCTION. 


TABLE  B.— (Continued.) 
LIMESTONES  OTHER  THAN  MARBLES. 


Description. 

Locality. 

Carbonate 
of  Lime. 

V 

Oxides  of 
Iron. 
Oxide  of 
Aluminum. 

Jjl 

Jl 

6.90 

0.96 
O.I9 

0.92 
1.76 

0-375 
i.6o 

Dolomite 

Lemont,  111  
Bedford  Ind  

45-80 

96.60 
97.26 
98.20 
97.26 
96.80 
95-31 
54-53 
41.88 
75.48 
49.16 
50.22 
54-78 
92.40 
54-70 
97.60 
95.16 

0.13 
0-37 
0.39 
0-37 

O.II 

1.  12 

36 

24-55 
6.81 
37-53 
37-39 
42-53 

I.  10 

44-93 

1.20 

2.307.00 

0.98 
0.49!  
0.39  

0.91  .  .  .  . 

0.903.16 
4-03.... 
1.70.... 
1.09!  
0.780.64 
0.360.31 
0.58..... 
0.20  

0.5o|  

15.90 

O.5O 
1.09 
0.63 
1.69 
0.70 
1.42 
16.22 
29-93 
14-45 
I3.O6 

8-54 
2-93 
1.70 

O.IO 

1.70 

1.20 

Oolitic 

Spencer,  Ind  
Bowling  Green,  Ky  
Minneapolis,  Minn  

««      (buff)             

"      (blue) 

Oolitic  

4 

, 

Kasota,  Minn  . 

< 

, 

Frontenac,  Minn  
Dayton,  Ohio  
Springfield,  Ohio  
Aubigney,  France  
Portland,  England  

i.o8* 
1.94 

Limestone  

Limestone  (Caen)  
(Oolitic)  

Description. 

Locality. 

Carbonate 
of  Lime. 

Carbonate 
of  Mag- 
nesia. 

Oxides  of 
Iron  and 
Aluminum. 

Insoluble 
Residue. 

Dolomite  
I      (white)  

Hastings,  N.  Y  
Sing  Sing,  N.  Y  
Tuckahoe,  N.  Y  

52.82 
53-24 
61.75 

45.78 
45.89 
38.25 



.... 

(white)  

Pleasantville  N   Y 

54  62 

45  °4 

O   21 

54  62 

43   91 

165 

Limestone  (white)  
(greenish)  
'         (white)  

Rutland,  Vt  •  
West  Rutland  Vt!  '.  '.  '. 

97-73 
85-45 
98  00 

-59 
14-55 

1.68 
o  57 

'          (bluish  gray).. 

Proctor   Vt  

98  17 

o  79 

o  005 

o  63 

(light  colored).. 

96  30 

3  06 

o  63 

East  Tennessee  

98  78 

0.67 

o  26 

.08 

Georgia  Marble  Co  

Georgia  

97  32 

I  60 

26 

Southern  Marble  Co  

98  96 

o.  13 

.  22 

ii 

o  88 

Carrara  (white)  

Italy  

99.24 
08  76 

0.28 

I   O8 

o  16 

APPENDIX. 


395 


TABLE  B.— (Continued.) 

ONYX   MARBLES. 


Source. 

Color. 

|j 
S 

£  3 

Carbonate 
of  Lime. 

Carbonate 
of  Mag- 
nesia. 

Carbonate 
of  Iron. 

Hacienda  del  Carmen,  Mexico  

171  87 

89  36 

3  oo 

5  24 

Mayer's  Station,  Arizona  

171  87 

93  93 

o  56 

5  5O 

Red  brown  

166  87 

93  82 

o  53 

4  06 

Suisin  City,  California  

170  62 

95  -48 

2.  2O 

Sulphur  Creek,      "        

167  5 

San  Luis  Obispo,  California  

White  

170 

93.68 

i  -43 

3  -93 

Rio  Puerco,  Valencia  County,  New 
Mexico  

Light  green  

179.37 

New  Pedrara,  Lower  California.  .  .  . 

Faintly  green  
White,  rose  tinted.  .  .  . 
White  

174-37 
173 
174 

J74  37 

90.16 

93-48 
96.86 
91  09 

1.66 
1.68 
0.24 
o  64 

6.97 
4.19 
2.79 
7  49 

Near  Lehi   Utah                  

Yellow 

170 

97  61 

o  23 

* 

it 
a 

!• 

Id 

4 

ui 

Source. 

| 

1 

M 

I 

"rt 
,fl 

§5 

£15 

£"8 

a 

Rutland  County,  Vt.  (sea  green)  
(unfading  green).  .  . 

65.02 
64.71 

16.02 

7.84 

5-44 
5-44 

2.99 
7-23 

2.00 
1-63 

4.16 
6.92 

1  '                  (purple)  

62.  37 

13.40 

4.  21 

7.66 

0.90 

7.2O 

Granville   N   Y   (red) 

T     7/1 

TO    T7 

I  43 

"?   92 

Old  Bangor   Penn   (dark) 

56  97 

2  69 

2.31 

2fi    DC 

Albion   Penn   (dark) 

55  J8 

25  57 

carbon 

2    IO 

4.OO 

Peach  Bottom  Region,  Penn.  (dark)  

58.37 

21.98 

10.66 

0-93 

I.  2O 

1-93 

1  These  are  the  valuable  constituents.    "  Peroxide  of  iron  is  probably  the  coloring  matter."., 


396  BUILDING  CONSTRUCTION. 

TABLE  c. 

LIST  OF  IMPORTANT  STONE  BUILDINGS  IN  THE  UNITED  STATES. 

[Given  to  enable  architects  to  see  the  appearance  and  weathering  qualities  of  the 
different  stones.*] 

GRANITE    BUILDINGS. 


Locality  of  Quarries. 

Name  of  Building. 

City. 

Dix  Island,  Me  
Hallowell    Me 

Post  Office  

New  York  City. 
Philadelphia,  Pa. 
Albany,  N.  Y. 
Augusta,  Me. 
Boston,  Mass. 

Albany,  N.  Y. 
Boston,  Mass. 
Charlestown,  Mass. 
Providence,  R.  I. 
New  York  City. 
Philadelphia. 
Savannah,  Ga. 
Mobile,  Ala. 
New  Orleans,  La. 
Washington,  D.  C. 
Concord,  N.  H. 
Denver,  Colo. 

Salt  Lake  City,  Utah. 

(New)  Post  Office 

State  Capitol 

State  Capitol  

Equitab'.e  Insurance  Co.  Building  
Post  Oliice 

Milford,  Mass 

City  Hall  
U.  S.  Custom  HOUPC  

Quincy,  Mass  

Bunker  Hill  Monument 

Post  Office  
A  stor  House  
Philadelphia  National  Bank  . 

Presbyterian  Church  
U   S   Custom  House 

U.  S.  Custom  House  
Congressional  Library  

Concord,  N.  H  

Gunnison,  Colo  
Little  Cotton  wood  Canon, 
Utah 

State  Capitol  
State  Capitol  

Mormon  Assembly  House  and  Temple..  .  . 

LIMESTONE    BUILDINGS. 


Locality  of  Quarries. 

Name  of  Building. 

City. 

Lockport,  N.  Y 

New  York  City. 
Boston,  Mass. 
Newport,  R.  I. 
New  York  City. 

(Fifth 
Avenue). 
Philadelphia,  Pa. 

Indianapolis,  Ind. 
Chicago,  111. 
St.  Louis,  Mo. 
New  Orleans,  La. 
Biltmore,  N.  C. 
Chicago,  111. 

St.  Paul,  Minn. 
Nashville,  Tenn. 

Bedford,  ^Ind  

Algonquin  Club  Building  

Residence  of  Mr.  Robert  Goelet  

«          

Manhattan  Life  Insurance  Building  
Mail  and  Express  Building  
American  Fine  Arts  Society  Building  
Residences   of   Cornelius  Vanderbilt  and 
VV.  K.  Vanderbilt  

| 

•          

Manufacturers'  Club  Building 

Tioga  Baptist  Church  .'  
State  Capitol 

.'!!'.!!!'.!"! 

Auditorium  Building  . 

Un  ion  Station  
Cotton  Exchange  Building 

Biltmore  
St.  Paul  Universalist  Church 

Cement,  111  

Central  Music  Hall 

St.  Paul,  Minn  
Kaosta,  Minn  

Catholic  Cathedral  

Post  Office  .. 

Bowling  Green,  Ky  

U.  S.  Custom  House  

*  Some  of  these  Stones  are  used  in  a  great  many  other  buildings  in  the  cities  mentioned,  the  idea  of 
the  author  being  to  give  only  one  or  two  examples  in  each  city. 


APPENDIX. 


397 


TABLE   C—  (Continued.) 

MARBLE   BUILDINGS. 


Locality  of  Quarries. 

Name  of  Building. 

City. 

Rutland  Vt 

(Old)  Parker  House,  on  School  Street  
St.  Patrick's  Cathedral  (in  part)  

Boston,  Mass. 
New  York  City. 
Philadelphia,  Pa. 
Washington,  D.  C. 

Boston,  Mass. 

Philadelphia,  Pa. 
Branford,  Conn. 
Knoxville,  Tenn. 
Memphis,  Tenn. 
Chattanooga,  Tenn. 
Boston,  Mass. 
Knoxville,  Tenn. 
Atlanta,  Ga. 
Jacksonville,  Fla. 

Lee,  Mass  

New  City  Buildings..   .  . 



Washington  Monument  (in  part)  

U.  S.  Capitol  Extension.. 

Tuckahoe,  N.  Y  

New  York  Life  Insurance  Building  

Montgomery  County,  Pa.. 
East  Tennessee  

Girard  College  

Blackstone  Memorial  Library  

U.  S.  Custom  House  and  Post  Office  
U.  S.  Custom  House  and  Post  Office  
U.  S.  Custom  House  and  Post  Office  
Trimmings,  Ames  Building     

i 

t 

Georgia 

St.  John's  Episcopal  Church  • 

4 

U.  S.  Custom  House  and  Post  Office  

SANDSTONE   BUILDINGS. 


Locality  of  Quarries. 

Name  of  Building. 

City. 

Longmeadow,   Mass,    (red 

Trimmings,  Trinity  Church  

Boston,  Mass. 
Chicago,  111. 
Boston,  Mass. 

Hartford,  Conn. 
New  York  City  (Fifth 
Avenue). 
New  York  City. 
Brooklyn,  N.  Y. 
Buffalo,  N.  Y. 
Philadelphia,  Pa. 
Chicago,  111. 
Baltimore,  Md. 
Ottawa,  Ont. 
New  York  City. 
Albany,  N.  Y. 
Chicago,  111. 
Lansing,  Mich. 

Houghton,  Mich. 

Minneapolis,  Minn. 
West  Superior,  Wis. 

Denver,  Colo. 
Cheyenne,  Wy. 

Kansas  City,  Mo. 
Denver.  Colo. 

Longmeadow,   Mass,    (red 

Portland,  Conn, 
(brownstone)  .  . 

«                    (i 

« 
Potsd  m,  N.  Y.  (red  stone) 

Ohio  Sandbtone  (buff  stone) 
Portage  Entry,  Mich,  (red 

Technology  (original)  Building  

Alumni  Hall,   Library  and  Art   School, 
Yale  College  

Residences  of  Win.   H.   Vanderbilt    and 
Messrs.  Twombly  and  Webb  
Astor  Library  
Academy  of  Design  (Montague  Street)  
Music  Hall  

Union  League  Club  Building.  . 

Residence  of  Geo.  H.  Pullman  

Parliament  Buildings  
Columbia  College 

All  Saints  Cathedral  

State  Capitol          .       .          ... 

State  Mining  School  Buildings 

Fond  du  Lac,  Minn,  (red- 
dish brown  stone)  
Kettle  River,  Minn  
Fort  Collins,    Colo,    (dark 

Westminster  Presbyterian  Church  
Board  of  Trade  Building  

Grace  Methodist  Church  

Fort  Collins,    Colo,    (dark 

Union  Pacific  Depot.   .  .  . 

Fort  Collins,   Colo,   (dark 

Manitou,  Colo,  (red  stone). 

Boston  Buildiner... 

BUILDING  CONSTRUCTION. 

TABLE  D. 
THE  EFFECT  OF  HEAT  ON  VARIOUS  BUILDING  STONES.* 


Kind. 

Locality. 

Weight  per  cubic 
foot  in  pounds. 

Ratio  of 
absorption. 

First  appearance 
of  injury.  De- 
grees F. 

8*4 

2-S^ 

HIP 

£"£« 

£o2 

General  cracking 
and  friability. 
Degrees  F. 

Rendered  worth- 
less. Deg.  F. 

^i 

t.~^. 

* 

Light  colored  granite  
Red  granite  
Carter's  Quarry  granite  

Hallowell,  Me  
Stark.  N.  H  
Woodbury,  Vt  

164.8 
164.1 
165.8 
16«.2 
165.5 

167.7 

168.2 
148.7 
150.  b 
151.5 
145.8 
140.8 
181.8 
154  8 
137.7 
166.6 
160.  B 
169.1 
168.5 
174  6 
171.3 
178.0 

169  4 

175.7 
176.6 
166.6 
169.2 
170  2 
165.3 

139.7 

1-790 
1-534 
1-784 
1-6M) 
1-394 

1-402 

1--,'SO 
1-27 
1-40 
1-240 
1-28 
1-20 
2-340 
l-'.'SII 
1-28 
1-280 
1-480 
1-316 
1-320 
1-298 

1-380 

1-320 
1-340 
1-320 
1-342 
1-49 
1-60 
1-80 

1-280 

800 
600 
800 
750 
700 

750 
700 
850 
900 
900 
800 
850 
900 
850 
8M 
850 
850 
900 
950 
900 
900 
950 

950 

1,000 
1.000 
1,000 

900 
700 
900 
800 
750 

800 
700 
900 
1,000 
950 

850 

900 
1,000 
900 
900 
850 
900 
950 
1.000 
1,000 
1,000 
950 

9W 
1,000 
1.000 
1,000 
800 
700 
700 

800 

950     1,000 

800     aso 

9501    l,noO 
80       900 
800       900 

850!      900 
8001      850 
950i    1,000 
1,100    1,200 
1,0.10!   1,000 
900    1.000 
950    1,000 
1,100!    1,200 
1,0001    1.200 
9501    1,200 
900    1,0.0 
,100    1,200 
.000    1,200 
.100    1,200 
.200    1,200 
,100    1,200 
,000  1    1,-00 

dl,?00 
1,200 
,100    1.200 
.100    1,200 
900    1,000 
800       900 
800       900 

1,100    1,200 

1.10ft- 
9M> 

1.200 
1,000 
900 

1.000 
900- 
1.100 
1,2UO 
1,100 
1.100 
1,000 
1,200 

i!soo 

1,200 
1.200 
1,200 
1,200 
1,200 
1,200 
1,200 
1,200 

1.200 
1,2«K 
1,200 
1,200 

i;ooo 

900 

900 

Common  granite  
Old  Dominion  Quarry  gran- 
ite 

Womfetock  Md 

Richmond,  Va  

Light  colored  granite  
Sandstone             

St  C'lond  Minn 

Portland,  Conn  
Seneca,  Md. 

Sandstone  
Potsdam  sandstone  
Berea  sandstone  

Nova  Scotia  

McBride's  Corners,  O  
Berea,  O  
Baltimore,  Md  

Bedford,  Ind  
Hamilton  Bounty,  O  
Springfield,  Penn  
Owen  Sound,  P.  O....  
Montreal  P  Q 

Cincinnati  limestone.     .  .  . 
Potts'  blue  limestone  
Dolomite  limestone  
Trenton  limestone  
Limestone  
Tuckahoe  marble  
Ashley  Falls  marble  ,. 
Snowflake  marble  
Tennessee  marble  

Isle  La  Motte,  Vt  
Westchester  County,  N.  Y. 
Ashley  Falls,  N.  Y  
Westchester  County,  N.Y.  . 
Dougherty's    Quarry,  East 
Tennessee  
Near  Harper's  Ferry,  Va.  .  . 
Isle  La  Motte  Vt 

Black  marble 

Sutherland  Falls  marble..  . 

Roxbury,  Mass  
Point  of  Rocks,  Md  
raps  a  La  Aisle,  P.  Q  
McMurtire   and    Chamber- 
lain Patent  

Conglomerate  
Artificial  stone  

*  From  "  Notes  on  Building  Stones,"  by  Dr.  Hiram  Cutting,  Montpelier,  Vt.,  1880. 

"  The  experience  of  the  citizens  of  North  Arkansas  is  that  marble  is  much  superior  to  the  sandstone 
in  withstanding  heat,  and  because  of  tnib  fact,  where  chimneys  are  built  of  sandstone  the  fireplaces  are 
lined  with  marble." 


APPENDIX. 


399 


-  8 


II 

«      H 


M      «! 
g     - 


g     3 


§2? 


I-H  ui  I-H  <N  o:  co  o:  o  •*  N        coTt;t-;r-;too5oqeo 

00  W  t^  ffl  CO  •*  O  CO  5C  5O     CO  00  r-I  tO  00  O  •*  C5 


ec  •*  i>  oq 

t^  OJ  1C  O 


a5  •*  r*  oq  Oi  i-  co  oq  •—  w  cj 

Issisi^i'lis 


oq  o*  »n  o  »  o  o 


8^88888 


®<S3        WOO  O<! 

s,||    S||       5  s 


.2  s 


§ 

It 

w- 

*r 


t    o 

a  S 


fllj 

W03'H 


-a      g  -a 

= 


CO-    2    -    2 


i.ti.-.,'i.   l_ 


;  XODOOQCN  CQO3 


00  05  W  O5  W  O  5C 


•^OOOOJOOQOO  OOOOOOO 


400  BUILDING  CONSTRUCTION. 

TABLE  F. 

SAFE  WORKING  LOADS  FOR  MASONRY. 
(From  the  Architect?  and  Builders'  Pocket  Book.) 


BRICKWORK   IN   WALLS   OR   PIERS. 

Tons  per  square  foot.  Eastern  Western 

Red  brick  in  lime  mortar 7            5 

' '  hydraulic  lime  mortar 6 

"               natural  cement  mortar,  I  to  3 IO             8 

Arch  or  pressed  brick  in  lime  mortar 8             6 

"         "          natural  cement 12             9 

"               "         "          Portland  cement 15  I2| 

Piers  exceeding  in  height  six  times  their  least  dimensions  should  be  increased  4  inches  in 
size  for  each  addititional  6  feet. 

STONEWORK. 

(Tons  per  square  foot.) 

Rubble  walls,  irregular  stones 3 

coursed  soft  stone 2^ 

"       hard  stone 5  to  16 

Dimension  stone,  squared  in  cement : 

Sandstone  and  limestone 10  to  20 

Granite 20  to  40 

Dressed  stone,  with  f -inch  dressed  joints  in  cement : 

Granite 60 

Marble  or  limestone,  best 40 

Sandstone 30 

Height  of  columns  not  to  exceed  eight  times  least  diameter. 

CONCRETE. 

Portland  cement,  I  to  8 8  to  20* 

Rosendale  cement,  I  to  6 5  to  IO 

Hydraulic  lime,  best,  I  to  6 5 

HOLLOW  TILE. 

(Safe  loads  per  square  inch  of  effective  bearing  parts.) 

Hard  fire-clay  tiles 80  Ibs. 

1 '     ordinary  clay  tiles 60    " 

Porous  terra  cotta  tiles 40   " 

MORTARS. 

lln  ^6-inch  joints,  3  months  old,  tons  per  square  foot.) 

Portland  cement,  I  to  4 40 

Rosendale  cement,  I  to  3 13 

Lime  mortar,  best 8  to  10 

Best  Portland  cement,  i  to  2,  in  J-inch  joints  for  bedding  iron  plates 70 

*  "  The  concrete  and  twisted  iron  columns  in  the  Pacific  Coast  Borax  Works,  16  inches  in  diameter 
.and  12  feet  high,  are  habitually  loaded  with  about  ;6  tons  to  the  square  foot."  -E.  L.  Ransome. 


APPENDIX. 


401 


TABLE  G. 

PROPERTIES  OF  TIMBER,  STONES,  IRON  AND  STEEL. 
(Values  for  strength  are  those  given  in  the  Architects'  and  Builders'  Pocket  Book.) 


.« 

^  -J> 

3  -a 

III 

ft* 

'f 

i« 

**"    §    «> 

s|r 

«_,       C       <U 

£      > 
fc/j—  •  <J 
•53.2 

£« 

Safe  Tensile  Strength, 
per  square  inch. 

Safe  Crushing 
Strength  in  pounds 
per  square  inch. 

ilf 

*2* 
£.s| 

111 

£«- 

iliJ 

ins 

:tjft- 
sjn 

Safe  Crushing 
Strength  across  the 
Grain,  pounds 
per  square  inch. 

Ch     t      t 

60 

Hemlock 

2  5 

52 

4.  1 

600 

4-7 

a  6 

06 

•7 

i  800 

36 

I  600 

^  V4- 

70  r  ' 

AC 

80 

800 

600 

60 

36 

a 

i  800 

625 

~ 

70 

35 

a 

i  200 

6e 

Slate          .                

J74 

25 

Granite             

167 

850 

18 

158 

55° 

18 

Marble       

170 

55° 

18 

139 

450 

12 

450 

2  6OO 

13  500 

308 

7  ooo 

Wrought  iron  

480 

IO  OOO 

IO  OOO 

665 

7  5^*° 

12  OOO 

888 

"                pins  

7  5°° 

12,000 

"                 rivets  

7>5°° 

15,000 

+  For  full  per 


MAKING  CELLARS  WATERPROOF. 


Quite  often  in  cities  it  is  desirable  to  construct  a  dry  basement  in  local- 
ities where  water  permeates  the  soil  to  within  a  few  feet  of  the  sidewalk. 

In  such  cases  it  is  necessary  not  only  to  make  the  walls  and  floor  water- 
proof, but  also  to  give  sufficient  thickness  to  the  floor  that  the  buoyant 
force  of  the  water  will  not  cause  it  to  break  through. 

To  make  the  cellar  water-tight  the  entire  area  of  the  cellar  should  be 
covered  with  concrete,  after  the  footings  of  the  walls  and  piers  are  in,  from 
3  to  6  inches  thick,  so  that  the  concrete  will  be  level  with  the  top  of  the 
footings.  A  narrow  course  of  brick  or  stone  should  then  be  laid  along  the 
centre  of  the  footings,  as  shown  in  Fig.  249,  to  form  a  break.  Upon  the 
top  of  the  footings  three  thicknesses  of  tarred  felt  or  burlap  should  then 
be  mopped  in  hot  asphalt,  the  felt  being  allowed  to  project  6  inches  on 


B  UILDING  CONS  TR  UC 1  'ION. 


\g/A£ts"%  i 
fi&iSjftim 

'-* 


each  side.  A  similar  layer  of  felt  and  asphalt  should  be  laid  over  the 
footings  of  all  piers,  engine  foundations,  etc.,  and  allowed  to  project  at 
least  6  inches  on  all  sides. 

After  the  external  walls  are  completed,  and  before  "  filling  in,"  the  pro- 
jecting felting  should  be  turned  up  and  mopped  with  hot  asphalt  against 
the  wall,  and  the  entire  outside  surface  of  the  wall  to  the  sidewalk  line 
covered  with  three  thicknesses  of  felt  laid  breaking  joints  in  hot  asphalt  and 
overlapping  the  felt  that  comes  through  the  wall.  For  further  protection 
this  covering  is  also  frequently  plastered  with  i  to  2  Portland  cement 
mortar. 

Before  the  completion  of  the  building  the  entire  cellar  floor  must  also  be 
covered  with  felt  in  hot  asphalt,  laid  in  at  least  three  thicknesses,  breaking 

joint  and  overlapping  the  felt  first  laid. 
On  the  top  of  the  felt  thus  laid  there 
should  then  be  laid  Portland  cement 
concrete  at  least  i  inch  thick  for  each 
3  inches  in  depth  of  the  water  above 
the  level  of  the  cellar  bottom,  with  a 
minimum  depth  of  6  inches. 

The    following    description   of   the 
.,   waterproofing  of  the  basement  of  the 
Herald  Building,  in  New  York  City,  is 
given   as   an    actual    example    of   the 
above  method  :  * 

In  this  building  the  printing  presses  are 
placed  in  the  basement,  and  great  pains  were 
taken  to  exclude  moisture  below  grade.  The 

footings  and  outside  basement  walls  were  covered  with  four-ply  burlap  mopped  on  solid, 
commencing  at  the  inner  edge  of  sidewalk  and  back  over  top  of  vault  and  down  the  outside 
of  the  wall  to  the  bottom  of  the  same,  thence  through  the  wall  and  turned  up  against  same 
for  connection  to  the  waterproof  course. 

Beneath  the  surface  of  the  entire  basement,  including  floor  of  vaults,  the  best  four-ply 
roofing  felt  was  mopped  on  solid,  and  similar  material  was  used  in  connection  with  all 
piers,  extending  in  each  case  through  the  entire  thickness  of  the  pier  and  beneath  the 
entire  surface  of  foundations  for  boilers  and  machinery. 

The  felt  was  securely  lapped  and  turned  up  around  all  walls.  Above  the  felt  4  inches 
of  concrete  was  laid  in  the  basement  and  16  inches  in  the  boiler  room. 

If  less  expensive,  hard  bricks  laid  in  cement  mortar  and  at  least  three 
courses  in  thickness,  may  be  used  instead  of  the  concrete  above  the  felt. 


*From  the  Eng intering  Record^  July  i,  1893. 


APPENDIX.  403 

STAIN  AND    DAMP-PROOFING.— ANTIHYDRINE. 

In  Section  301  attention  has  been  called  to  the  frequent  staining  of 
plastering  applied  on  fireproof  tiling,  which  has  proved  a  source  of 
much  trouble  in  getting  a  fine  decorative  surface,  the  stains  showing 
even  through  oil  paint. 

Similar  trouble  is  also  sometimes  experienced  with  plastering  ap- 
plied directly  to  the  brickwork  of  outside  walls,  so  that  any  prepara- 
tion which  will  prevent  these  stains  is  very  desirable  and  should  be 
known  to  all  architects.  In  Section  301  an  English  preparation, 
known  as  Duresco,  is  recommended  for  this  purpose,  but  the  author 
is  informed  that  this  material  is  not  now  carried  in  stock  in  this 
country. 

A  new  preparation  called  Antihydrine  is  now  made  in  this  coun- 
try, however,  which  appears  to  be  an  excellent  article  both  for  pre- 
venting the  stains  in  plastering  due  to  the  mason  work  and  for  damp- 
proofing,  and  seems  to  have  given  excellent  satisfaction. 

Antihydrine  is  a  high  grade  of  ashphalt  varnish,  which  can  be  ap- 
plied cold  to  any  porous  surface  without  being  absorbed  by  the  ma- 
terial or  becoming  too  thick  in  places.  It  is  said  to  absolutely  pre- 
vent the  passage  of  moisture,  which  is  generally  admitted  to  be  the 
agent  which  produces  the  stains  in  the  plastering. 

To  prevent  the  staining  of  plastering  it  should  be  applied  with  a 
brush  directly  to  the  intide  surface  of  the  mason  work,  whether  the 
latter  be  brick,  stone  or  fireproof  tiling.  But  one  coat  is  required. 

About  twenty-four  hours  after  the  Antihydrine  is  applied,  and 
while  it  is  still  soft,  the  plastering  should  be  applied  in  the  usual  way. 
It  has  been  found  that  plastering  adheres  to  this  coating  equally  as 
well  as  to  brickwork,  and  that  it  dries  much  more  quickly  and  evenly, 
and  that  decorating  can  be  safely  applied  within  a  few  days  after  the 
last  coat  of  plaster  is  dry. 

As  the  Antihydrine  absolutely  prevents  the  passage  of  moisture, 
furring  the  walls  can  be  safely  omitted,  thereby  effecting  a  saving  in 
cost  and  in  the  thickness  of  the  walls,  and  also,  it  is  claimed,  in  the 
time  required  for  drying  the  plastering. 

Mr.  Louis  De  Coppet  Berg,  of  Cady,  Berg  &  See,  architects,  states 
that  his  firm  now  omits  furrings  entirely,  covering  the  wall  instead 
with  Antihydrine,  and  that  they  also  cover  all  fireproof  surfaces  of 
partitions,  ceilings,  etc.,  with  this  material  before  plastering. 

It  has  also  been  found  to  be  an  excellent  base  for  whitewash,  the 
second  coat  drying  out  perfectly  white  and  free  from  stains. 


404 


B  UILD1NG  CONS  TR  UC  TJ  ON. 


When  used  under  whitewash,  however,  the  Antihydrine  should  be 
allowed  to  harden  thoroughly  before  applying  the  whitewash,  and  at 
least  two  coats  of  the  latter  should  be  applied. 

Antihydrine  is  also  recommended  for  coating  the  built-in  surfaces 
of  limestone  and  marble,  as  it  prevents  the  staining  of  the  stone  by 
the  mortar.  When  this  material  is  used  common  mortar  may  be  used 
for  laying  the  backing. 

The  manufacturers  also  state  that  they  have  found  this  preparation 
an  excellent  material  for  priming  the  outside  of  brick  walls  that  are 
to  be  painted,  as  it  takes  the  paint  perfectly,  and  two  coats  of  paint 
over  one  coat  of  Antihydrine  makes  a  perfect  job  that  will  not  peel 
or  crack  off. 

The  material  is  quite  inexpensive. 

Mr.  Berg  states  that  plastering  that  has  already  become  stained 
cannot  be  improved  by  applying  Antihydrine  to  its  surface,  it  being 
necessary  to  apply  the  Antihydrine  to  the  wall  before  plastering. 

THE  ROEBLING  FIREPROOF  FLOOR. 

Additional  Data  Relative  to  Weight  and   Strength.— 

On  page  290  is  given  the  actual  weight  of  various  systems  of  fireproof 
floor  construction  when  built  between 
i2-inch  beams.  The  concrete  used  in 
the  Roebling  "floor  in  this  test  had 
broken  stone  aggregate.  In  nearly  all 
buildings  where  this  construction  is 
used,  however,  the  concrete  is  made  of 
cement,  sand  and  steam  ashes  or  cin- 
ders, which  greatly  decreases  the 
weight.  The  following  table  gives  the 
average  weight  per  square  foot  for 
floors  constructed  of  concrete  mixed 
in  the  proportion  of  i  part  Portland 
cement,  2  of  sand  and  5  of  cin- 
ders, the  weights  being  based  upon 
results  obtained  by  weighing  the 
materials  taken  from  sections  of  12 
and  i5-inch  levels  two  months  old 
and  perfectly  dry.  Of  course  when 

first  laid  they   will   exceed    these   weights. 

The  table  also  gives  the  maximum  spacing  of  floor  beams  for 


APPENDIX. 


405 


different  heights  of  arches,  measured  from  under  side  of  beam  to 
top  of  arch. 


WHEN   CONCRETE  IS 

MAXIMUM     SPACING 

TO     BE     LEVELED 
ABOVE   UNDER 
SIDE      OF      FLOOR 
BEAMS       TO       A 

OF     IRON      FLOOR 
BEAMS      (l  N  D  E- 

PENDENT  OF  SIZE 
OF  BEAMS)  SHOULD 

THICKNESS     OF 
CROWN   AT  CEN- 
TRE  OF  ARCH. 

WEIGHT  PEK  SQUARE 
FOOT,     INrLUDINU 
ONLY     CONCREIE 
AND   WIRE. 

HEIGHT    OF 

NOT   EXCEED 

8  inches. 

4  feet  o  inches. 

3  inches. 

28  pounds. 

9       " 

4    "    6     " 

3      " 

30     " 

10          " 

5    "    o     •« 

3      " 

33 

12 

6    "    o     " 

3      " 

39 

15         " 

7    "    6     " 

3      " 

53 

In  spans  of  over  5  feet  allow  \\  inches  clear  rise  for  each  foot  of 
span.  The  weights  given  are  for  concrete  to  level  indicated  in  first 
column,  with  3-inch  crown,  and  for  all  wire  construction,  including 
arch  wire  for  floors  and  lathing  for  ceiling.  Add  for  plaster  8  to  10 
pounds  per  square  foot.  Weight  of  structural  iron  and  of  wood  or 
other  finished  floor  must  also  be  added  for  total  dead  load  of  floors. 

All  floor  beams  should  be  tied  together  at  intervals  of  about  eight 
times  their  depth,  and  should  be  framed  level  and  flush  on  the  un- 
der side  where  flat  ceilings  are  desired. 

The  ceiling,  when  plastered,  finishes  about  if  inches  below  the 
lower  flange  of  floor  beams. 

Test  of  Strength  and  Resistance  to  Fire. — As  the  great  strength  and 
fire-resisting  qualities  of  concrete  arches  do  not  yet  appear  to  be 
generally  appreciated,  the  following  report  of  a  severe  test  of  an  arch 
built  on  the  Roebling  system  is  given  for  the  benefit  of  any  who  may 
yet  be  skeptical  on  the  subject,  the  description  and  illustration  being 
taken  from  the  Engineering  News  of  February  4,  1897: 

The  floor  arches  shown  in  section  in  Fig.  250  were  concreted  on  September  26, 
1896,  and  on  October  28  the  fire  test  was  made.  The  floor  was  loaded  uniformly 
with  150  pounds  to  the  square  foot,  and  at  10  A.  M.  fires  were  lighted  on  the  grates 
beneath  the  floor.  The  temperature  on  the  under  side  of  the  floor  was  maintained 
at  above  2,000°  F.  for  three  hours,  and  at  3  P.  M.  a  powerful  stream  from  a  fire 
engine  was  thrown  against  the  under  side  of  the  floor,  which  was  at  the  time  so  hot 
as  to  glow. 

After  the  floor  cooled,  on  the  following  day,  the  load  on  the  floor  was  increased 
to  600  pounds  per  square  foot,  still  without  signs  of  failure. 

On  December  u,  12  and  14  a  section  of  one  floor  arch,  2  feet  6  inches  long  and 
4  feet  span,  was  isolated  from  the  rest  of  the  floor  by  cutting  openings  in  the  con- 
crete from  beam  to  beam  on  each  side.  Upon  this  was  built  a  brick  pier  2  feet  6 


4o6  BUILDING  CONSTRUCTION. 

inches  square  and  a  foot  high,  and  upon  this  pier  was  placed  a  platform  of  plank  7^- 
feet  square.  This  was  then  loaded  with  brick  and  stone,  as  shown  in  the  figure  until  a 
weight  of  40,000  pounds  had  accumulated  and  the  pile  became  so  top-heavy  that 
further  additions  were  deemed  unsafe.  The  deflection  of  the  arch  under  this  load 
was  I  inch,  and  after  the  load  was  removed  this  was  decreased  to  f  inch. 

The  concrete  in  this  arch  was  composed  of  i  part  Aalborg  Port- 
land cement,  2  parts  sand  and  5  parts  steam  cinders. 

THE    EXPANDED    METAL  SYSTEMS    OF    FLOOR 
CONSTRUCTION. 

The  use  of  expanded  metal  in  combination  with  concrete  for  floor 
construction  has  become  so  extensive  that  a  description  of  the  more 
common  methods  of  using  it  may  be  considered  as  necessary  to 
complete  the  subject  of  fireproof  floor  construction. 

Two  primary  methods  of  construction  are  employed,  the  adoption 
of  the  one  or  the  other  depending  upon  the  character  of  the  build- 
ing, the  purpose  for  which  it  is  to  be  used  and  the  form  of  ceiling 


Fig. 


desired.  In  one  of  these  methods,  illustrated  by  Nos.  3,  5  and  8 
Fig.  252,  the  floor  is  constructed  as  a  composite  slab,  on  the  same 
principle  as  the  Ransome  floors,  the  expanded  metal  forming  the 
tension  member.  In  the  other  method  the  arch  principle  is  em- 
loyed,  the  expanded  metal  being  used  as  a  centre  for  the  concrete. 

The  expanded  metal  used  in  floor  construction  is  made  by  the  same 
process  as  the  expanded  lath,  but  of  heavier  metal,  usually  from 
Nos.  10  to  1 6,  and  of  either  3-inch  or  4-inch  mesh,  the  appearance  of 


APPENDIX. 


407 


the  floor  material  being  as  shown  in  Fig.  351,  which  is  about  one- 
quarter  size. 

Fig.  252  shows  four  styles  of  flooring  which  have  been  found  best 
adapted  to  the  usual  requirements.  The  spans  indicated  are  those 
which  are  usually  the  most  economical,  but  they  can  be  varied  to 
suit  the  divisions  of  the  building. 

Systems  3  and  5  are  most  commonly  used   in   office  buildings, 


No.  3. — Span,  6  feet  ;  weight,  35  Ibs.  per  sq.  foot. 


No.  5.— Span,  about  8  feet ;  weight.  30  Ibs.  per  sq.  foot. 


No.  8. — Span,  4  feet  ;  weight,  35  Ibs.  per  sq.  foot. 


No.  9. — Span,  6  feet ;  weight,  45  Ibs.  per  sq.  foot. 
Fig.  252. 

hotels,  etc.  Where  the  rooms  are  uniformly  arranged,  with  the  par- 
titions placed  under  one  of  the  beams,  system  No.  5  may  be  used 
to  advantage,  and  a  considerable  saving  in  the  height  of  the  building 
effected,  as  only  about  5  inches  of  this  height  is  taken  up  by  the 
floor. 

No.  8  is  especially  adapted  to  light  floor  loads  such  as  are  usually 
found  in  dwellings,  apartment  houses,  etc.,  and  where  the  beams  do 
not  need  to  be  very  heavy. 

No.  9  is  constructed  by  springing  sheets   of  expanded  metal  be- 


408  BUILDING  CONSTRUCTION. 

tween  the  floor  beams  and  filling  on  top  with  concrete  composed  of 
Portland  cement,  sand  and  steam  cinders.  It  is  adapted  to  the  heav- 
iest loads  and  to  spans  of  from  6  to  7  feet,  or  so  that  8-foot  sheets 
may  be  used  for  the  arches. 

The  thickness  of  the  floor  slabs  is  usually  about  3  inches,  and  of 
the  arch  at  the  crown  from  2^  to  3  inches.  The  weights  given  are 
exclusive  of  the  beams  and  wood  or  tile  flooring. 

Repeated  tests  have  demonstrated  that  either  of  the  flat  systems 
have  abundant  strength  for  the  ordinary  loads  in  office  buildings, 
apartments,  etc.,  and  the  arch  system  may  be  safely  used  for  the 
heaviest  warehouses.  The  tests  have  also  shown  that  when  over- 
loaded, such  floors  do  not  fail  suddenly,  but  quite  gradually,  thus 
giving  warning  of  their  dangerous  condition. 

TERRA  BLANCA  FIREPROOF  TILING. 

This  is  a  fireproof  material  composed  of  silicates,  alkalies,  iron  and 
gypsum,  mixed  with  cinders  and  slag  from  blast  furnaces. 

It  resembles  in  its  appearance  the  various  compositions  of  plaster 
that  have  been  placed  on  the  market,  but  the  author  believes  that  it 
is  superior  to  them  in  its  fire  and  water-resisting  qualities. 

The  material  is  probably  not  surpassed  even  by  porous  terra  cotta  as 
a  non-conductor  of  heat,  and  it  does  not  appear  to  be  greatly  injured 
by  intense  heat,  although,  like  all  plastic  materials,  the  surface  soft- 
ens by  recalcining  and  also  upon  the  application  of  water. 

Terra  Blanca  is  remarkably  light  in  weight,  and  for  this  reason  is 
well  adapted  for  partitions  and  for  ceilings  under  wooden  joists.  It 
is  a  non-conductor  of  sound;  plastering  dries  on  it  very  quickly,  and 
it  is  inexpensive  and  easily  put  up.  It  is  not  capable  of  sustaining 
heavy  weights,  and  should  not  be  used  for  bearing  partitions,  but 
there  are  many  places  where,  in  the  opinion  of  the  author,  it  could  be 
used  to  good  advantage,  especially  in  lessening  the  fire  risks  in 
wooden  buildings  and  in  making  them  more  sound  and  vermin-proof. 
It  is  also  used  for  fireproofing  steel  construction. 

Although  but  very  recently  placed  on  the  market,  Terra  Blanca  has 
been  used  in  several  notable  buildings  in  Chicago  and  in  numerous 
buildings  elsewhere. 

It  is  moulded  into  slabs  from  i  to  2  inches  in  thickness,  13^  inches 
wide  and  48  inches  long;  these  slabs  can  be  applied  to  wooden  stud- 
ding or  floor  beams,  or  to  brick  walls,  by  means  of  capped  wire  nails. 

The  partition  slabs  are  made  of  the  shape  shown  in  Fig.  253  and 
3,  4,  5  and  6  inches  in  thickness.  These  partition  tile  can  be  laid  up 


APPENDIX. 


409 


without  mortar,  small  steel  rods  being  used  for  holding  them  in  place, 
as  shown  in  Detail  A,  or  they  may  be  set  in  mortar  and  the  rods 
omitted. 


Fig.  253. 

Nails  can  be  driven  into  the  tiles  without  breaking  or  chipping,  and 
the  tiles  can  also  be  readily  cut  with  a  saw.  The  manner  of  applying 
the  tiles  and  slabs  to  wooden  buildings  is  also  shewn  in  Fig.  253. 


4io  BUILDING  CONSTRUCTION. 

The  weight  per  square  foot  of  the  i-inch  slabs  is  4  pounds;  of  the 
3-inch  partition  tile,  9  pounds;  of  the  4-inch,  n  pounds;  of  the 
5-inch,  12  pounds,  and  of  the  6-inch,  15  pounds.  A  partition  of 
4-inch  tiles,  with  two  light  coats  of  plaster  on  each  side,  will  not 
much  exceed  in  weight  an  ordinary  lath  and  plastered  partition  with 
2X4-inch  studding. 

PELTON'S  SYSTEM  OF  RELEASED  WALL  FACING. 

During  the  past  four  years  (1892-1896)  Mr.  John  Cotter  Pelton, 
architect,  has  developed  and  patented  a  system  of  released  wall  fac- 
ing which  has  met  with  commendation  from  many  prominent  archi- 
tects, and  which  the  author  believes  to  be  sufficiently  practicable  as 
to  interest  all  architects  and  students.  The  essential  feature  of  this 
invention  is  the  idea  of  supporting  a  .costly  facing  of  stone,  marble  or 
terra  cotta  from  a  wall  of  common  masonry,  or  from  a  steel  frame  by 
means  of  metal  anchors  and  brackets,  which  hold  the  facing  away 
from  the  wall  or  frame  and  also  permit  of  its  being  set  after  the  sup- 
porting wall  is  completed.  The  general  principle  of  construction  is 
quite  clearly  indicated  by  Fig.  254. 

The  advantages  claimed  for  this  system  are:  First,  economy  of 
material  in  the  facing;  second,  saving  in  time  required  to  complete 
the  building  ready  for  occupancy;  third,  protection  against  the  pen- 
etration of  moisture;  fourth,  elimination  of  the  bad  effects  of  settle- 
ment in  the  walls  and  the  staining  of  the  facing  from  the  backing; 
fifth,  protection  against  exterior  fire.  Of  these  advantages  the  first 
and  second  will  probably  have  the  most  influence  in  extending  the 
use  of  the  system,  as  they  have  a  direct  bearing  upon  the  cost  and 
financial  returns  of  the  building.  The  other  advantages,  however, 
are  perhaps  the  most  important  from  a  constructive  standpoint. 

As  the  facing  is  treated  merely  as  an  external  covering,  principally 
for  architectural  effect,  and  has  nothing  to  support,  it  can  be  made 
very  thin,  thus  permitting  the  use  of  expensive  materials,  which, 
with  the  ordinary  method  of  construction,  would  be  prohibited  on 
account  of  the  cost. 

The  anchors  which  support  the  facing  being  built  into  the  sup- 
porting wall  as  it  progresses,  the  facing  can  be  applied  after  the  roof 
is  on  and  while  the  building  is  being  finished  on  the  inside,  or  even 
after  the  building  is  occupied.  Hence  a  building  faced  with  marble 
under  this  system  could  be  completed  ready  for  occupancy  in  about 
the  same  time  that  would  be  required  if  the  walls  were  of  plain  brick- 
work, and  ample  ti/ne  allowed  for  cutting  and  setting  the  facing,  and 


APPENDIX. 


41  r 


even  for  quarrying  the  stone.  In  fact,  any  unavoidable  delays  with 
the  stonework,  such  as  strikes,  unfavorable  weather,  etc.,  need  not 
delay  the  finishing  of  the  interior  of  the  building. 

As  a  protection  from  dampness  the  advantage  of  this  system  is 
obvious,  as  a  continuous  air  space  is  provided  between  the  facing 
and  the  supporting  wall,  with  only  the  metal  anchors  connecting  the 
two. 

The  facing  being  applied  after  the  supporting  wall  is  completed, 
all  settlement  in  the  latter  will  have  taken  place  before  the  orna- 


mar 


^j 


Detail  of  Anchors. 


Fig.  254 


mental  work  is  set,  thus  avoiding  the  cracks  which  frequently  occur 
in  facings  that  are  bonded  into  a  brick  backing.  Of  course  any  set- 
tlement in  the  foundations  would  affect  the  facing  as  well  as  the  sup- 
porting wall.  A  facing  supported  in  this  way  will  also  serve,  while 
it  endures,  to  protect  the  supporting  wall  from  external  fires,  and 
should  a  portion  or  all  of  the  facing  be  injured  beyond  repair,  it  can 
be  removed  and  new  pieces  substituted.  A  facing  of  either  marble 


4i2  BUILDING  CONSTRUCTION. 

or  limestone  would  probably  protect  the  structural  wall  from  serious 
damage  from  any  ordinary  fire;  and  even  when  the  fire  is  inside  the 
building  this  method  of  facing  is  likely  to  prove  an  advantage,  as  in 
such  cases  the  flames  generally  destroy  the  stonework  around  the 
exterior  doors  and  windows,  and  with  a  released  facing  the  injured 
stones  could  be  replaced  if  the  structural  wall  was  not  weakened. 

This  system  of  construction  has  been  adopted  in  a  few  buildings  in 
California,  of  which  the  Public  Library  at  Stockton,  a  building 
in  the  Renaissance  style  and  designed  by  Mr.  Pelton,  is  the  most 
elaborate. 

"  This  building  stands  on  a  corner  and  has  exposed  about  210  feet 
of  frontage,  the  whole  of  which  is  of  white  marble  on  a  light  gray 
granite  foundation  wall  7  feet  high.  The  structural  walls  are  of 
brick,  24  inches  in  thickness,  and  the  ashlar  is  2\  inches  thick,  with 
an  air  space  of  af  inches.  The  whole  of  the  work  on  this  building, 
except  the  finishing  coat  of  plaster  and  the  interior  woodwork,  was 
completed  before  the  marble  for  the  facade  was  delivered  upon  the 
ground.  The  whole  cost  of  the  exterior  marble  work  was  bss  than 
$17,000,  in  which  is  included  not  less  than  $3,000  for  carving  and 
the  cost  of  six  monolithic  columns  16  feet  in  height." 

The  anchors  or  carriers  in  this  building  were  all  set  and  adjusted 
by  an  engineer,  so  as  to  secure  perfect  alignment,  and  no  difficulty 
appears  to  have  been  encountered  in  any  portion  of  the  work, 
the  appearance  of  the  building  on  completion  being  the  same  as  if 
constructed  in  the  ordinary  way. 

"  At  one  time  during  the  progress  of  the  work  there  were  men  at 
work  at  not  less  than  five  different  parts  of  the  building  and  on 
eight  different  levels. 

"  Every  stone  sent  to  the  staging  as  correct  in  size  was  set  without 
trimming;  in  fact,  fitting  and  trimming  were  not  known  upon  the 
staging.  The  only  cutting  known  to  have  been  done  in  the  work  of 
setting  was  the  small  amount  of  channeling  required  for  the  carriers, 
and  this  work  hardly  occupied  the  time  of  one  workman." 

The  shape  and  size  of  the  carriers  or  anchors  will  necessarily  de- 
pend a  good  deal  upon  the  size  and  weight  of  the  pieces  to  be  sup- 
ported. The  shape  of  some  of  the  carriers  used  in  the  Stockton  Li- 
brary is  shown  in  Fig.  254.  To  insure  the  successful  setting  of  the 
facing  the  carriers  must  be  set  with  great  exactness,  and  Mr.  Pelton 
recommends  that  an  engineer  be  employed  to  give  both  the  horizon- 
tal and  plumb  lines. 


APPENDIX.  413 

The  window  frames  should  be  set  before  the  facing  and  the  latter 
built  around  them. 

As  stated  in  the  first  paragraph,  this  system  of  construction  has 
been  patented  by  Mr.  Pelton,  and  architects  who  wish  to  adopt  it 
should  consult  with  him  in  regard  to  royalty,  details  of  the  carriers, 
etc. 


INDEX   TO   ADDITIONS. 

[SECOND   EDITION.] 


Antihydrine  damp-proofing  material 4°3 

Brick  fireplaces 2420 

Brick  spiral  stairs 242^ 

Colored  sand  finish 356 

Concrete  steps 369^ 

Door  and  window  frames  in  thin  fireproof  partitions 35  * 

Expanded  metal  furring  in  fireproof  buildings 35°a 

Expanded  metal  systems  of  floor  construction 406 

Pclton's  system  of  released  ashlar 410 

Preventing  stains  in  plastering „ 403 

Roebling's  fireproof  floor,  weight  and  strength  of 404 

Stain  and  damp-proofing — Antihydrine 4°3 

Terra  Blanca  fireproof  tiling 408 

Thin  fireproof  partitions,  door  and  window  frames  in 351 

Weight  and  strength  of  the  Roebling  fireproof  floor 404 


INDEX. 


Actual  weight  of  fireproof  floors. . . .  290 
Adhesion   of  mortars  to   brick  and 

stone H5 

Advantages  of  hard  wall  plasters. . .  339 

"  "    metal  lathing 325 

Alum  in  mortar 116 

American  marbles,  description  of . .  129 

"         Portland  cement 104 

"         sandstones 132 

"         slates 137 

Analysis  of  natural  cements 101 

Anchoring  walls  to  floor  joist 217 

Arches,  brick,  236;  centres  for,  173; 
elliptical,  171  ;  flat,  stone,  172  ; 
floor,  262;  inverted,  in  founda- 
tions, 67;  relieving  beams  over, 

170;  rubble,  173;  stone 167,  170 

Area  walls 7° 

Areas,  steps  in 82 

"       window  and  entrance 81 

Ashlar,  backing  of,  179;  description 
of,  151,  153;  laying  out,  177; 
specifications  for,  376;  thickness 

of,  177;  tying  and  bonding 178 

Asphalt 227 

Atmospheric  action  on  stones I42 

B 

Backing  of  stone  arches 170 

Backing  of  stone  ashlar 177 

Batter  boards 13 

Bay  windows,  supports 305,  311 

Bearing  power  of  soils 19,     20 

Blue  shale 134 

Bond  in  brickwork 214 

"     stones  and  templates. .......  180 

"     timbers 225 

Bonding  of  ashlar 177 

"          "  brick  arches 235 

"  hollow  walls 230 

"         "  stone  foundation  walls..    70 

Bostwick  steel  lath 325 

Bracing  the  walls  of  buildings 91 

Brick  arches 235 

chimneys 238 

cornices 2io 

footings 65 

kilns 95 

nogging 238 

vaults 237 

veneer  construction 233 

walls,  construction  of 214 


Bricks,  advantages  of,  189;  color 
of,  202;  composition  of,  189;  man- 
ufacture of,  190;  requisites  of 
good,  203;  size  and  weight  of,  202; 
specifications  for,  378;  strength  of,  204 
Bricks,  classes  of :  arch,  201 ;  dry 
pressed,  194,  201;  enameled,  197; 
fire,  200;  glazed,  197;  hand- 
made, 190;  machine-made  com- 
mon, 191;  paving,  199;  salmon, 
201;  soft  mud,  191;  stiff  mud, 

192;  stock 201 

Brickwork,  204;  grouting,  206;  lay- 
ing, 205,  207;  laying  in  freezing 
weather,  208;  measurement  of, 
246;  ornamental,  209;  specifica- 
tions for,  377;  striking  the  joints, 
206;  thickness  of  joints,  205;  wet- 
ting the  bricks,  208;  efflorescence 
on,  243;  strength  of. .  ..245,  399,  400 

Briquettes,  cement  for  testing 107 

Broken  ashlar 153 

Brownstone,  see  sandstone 131 

Building  stones,  absorption  of,  147; 
color  of,  140;  durability  of,  141; 
hardness  and  strength,  144;  meth- 
od of  finishing,  144;  oxidation  of, 
143;  protection  and  preservation  \ 
of,  148;  resistance  to  fire,  145; 
seasoning  of,  148;  selection  of, 
139,  145;  solution,  143;  testing..  146 

Buildings,  staking  out 13 

Buildings,  stone,  list  of 395 

Burning  bricks,  see  also  kilns 195 

Byrkit-Hall  sheathing  lath 319 


Caissons,  for  foundations 57 

Capping  of  piles,  concrete,  39;  gran- 
ite, 39;  grillage 40 

Carton  pierre 344 

Cast  iron  arch  girders 303 

chimney  caps 316 

coal  hole  covers 316 

door  guards 313 

lintels 302 

skevvbacks 313 

Ceilings,  fireproof 293 

Cellar  walls,  dampness  in 80 

Cellars,  making  waterproof..   401 

Cement,  Fort  Scott,  100;  Keene's, 
343 ;  Laf arge,  1 1 1 ;  Louisville,  100 ; 


4i6 


INDEX. 


Milwaukee,    100;    Portland,    103; 
Roman,     103;     Rosendale,     100; 

Utica 100 

Cement  mortars,  data  for  estimating, 
114;  proportion  and  mixing,  112; 
specifications  for,  375,  379; 
strength  of,  113,  115,  400;  use.  .  in 

Cement  walks 85,  368 

"       'wall  plasters 336 

Cements,  natural,  analysis  of,  101; 
characteristics  of,  102;  how  made, 
distribution  and  varieties  of,  99; 

testing 102 

Centres  for  arches 173 

Chemical  wall  plasters 336 

Chimney  caps  of  cast  iron 316 

Chimneys,  construction  of 238 

Clay  soils 17 

Cleaning  down  brickwork 243,  381 

stonework 183,  377 

Coal  hole  covers 316 

Color  of  bricks 202 

"       building  stones 140 

"       natural  cements 102 

"       Portland  cements 105 

Colored  mortars 122 

Columbian  fireproof  floors 287 

Column  casings,  fireproof 294,  295 

Concrete,  characteristics  of,  n8; 
data  for  estimating,  122;  deposit- 
ing, 121 ;  materials  for,  mixing, 
119;  proportions  for,  120;  specifi- 
cations for,  373;  strength  of..i2i, 

366,  400 
Concrete  and  tension  bar  footings, 

42 ;  fl  x>rs 279 

Concrete  beams 363 

"  building  construction,  357; 
details  of,  363;  examples  of,  358; 
expansion  and  contraction,  367; 

surface  finish 364 

Concrete  capping  for  piles 39 

"        floor  construction 278 

footings 63 

mixing  machines 366 

sidewalks,  85;   monolithic,  368 
"         for  monolithic  construction,  365 

Connecticut  brownstone 132 

Construction  of  brick  walls,  214; 
anchoring,  217;  bond,  214;  cor- 
beling for  floor  joist,  220;  damp- 
proof  courses,  227;  hollow  walls, 
229,  232;  thickness  of  walls,  223,  225 

Construction  of  chimneys 238 

"  of   concrete  buildings, 

358,  363 

of  fireplaces 242 

Corbeling  brick  walls  for  floor  joist,  220 

Cornices,  brick 210 

plaster,    341;    terra  cotta 
grounds  for 351 


Cost  of   concrete,    122;    monolithic 

construction 361,  363 

Cost  of  metal  lathing 355 

"      plastering  and  stucco 355 

"      staff 349 

Cracks  in  walls 226 

Crandall,  for  cutting  stone 156 

Curtain  walls 225 

Cut  stonework,  150,   188;  specifica- 
tions for 376 

Cutting  off  piles 39 


Dampness  in  cellar  walls,   how  to 

prevent 80 

Damp-proof  courses 227 

Damp- proofing     brick     and     stone 

walls 243 

Dense  hollow  tiling 261 

Description  of  granites 125 

"             limestones 127 

"              marbles 129 

"             sandstones 133 

slates 137 

Diaper  work  in  brick 212 

Distribution  of  granites 125 

"             limestones 127 

marbles 129 

"             natural  cements. ...  99 

"             sandstones 133 

"             slates 136 

Door  bumpers  and  guards,  cast  iron,  316 

Durability  of  building  stones 141 

"          concrete  buildings. ...  357 

"          iron  in  concrete 42 

lime  mortar 96 

"          terracotta 251 


Effect  of   atmosphere   on   building 

stones 142 

Effect  of  climate  on  stones 140 

"       heat  on  building  stones  . .  398 
' '       heat  and  cold  on  building 

stones 141 

Efflorescence  on  brickwork 243 

Elliptical  stone  arches 171 

Enameled  bricks 197 

End-method  hollow  tile  floor  arches,  265 
Estimating  the  cost  of  concrete.  ...  122 

"             "    quantities  of  mate- 
rials required  in  mortar 114 

Examples  of  concrete  buildings. ...  358 
Excavation,  specifications  for,  372; 
staking  out  for,  13;  superintend- 
ence of 29 

Expanded  metal  lath 324 

Expansion   and   contraction  of  ce- 
ment mortars nS 


INDEX. 


Expansion  and  contraction  of  con- 

c  etc 367 

External  plastering 344 


Fawcett  fireproof  floor 279 

Fibre  for  plaster , 329 

Fibrous  plaster 344 

Fire  bricks 200 

Fireplaces 242 

Fireproof  ceilings 293 

"        floors 262 

"        roofs 292 

vaults 368 

Fireproofing:  by  whom  it  should 
be  done,  258;  floor  construction, 
262;  girder  and  column  casings, 
294;  partitions,  297;  roofs,  292; 
selection  of  a  system  of,  291;  spec- 
ifications for,  382;  wall  furring. .  299 
Fireproofing  materials:  clay  pro- 
ducts, 260;  concrete 262 

Flat  arches,  brick,  237;  stone 172 

Floor  arches,  see  floor  construction,  262 
Floor  construction,  262;  Columbian 
floor,  287;  concrete  and  metal 
floors,  278;  Fawcett  floor,  276; 
floor  and  ceiling  finish,  271; 
Guastavino  floor,  275;  hollow  tile 
floors,  flat,  263;  segmcntal,  272; 
Metropolitan  floor,  282;  protec- 
tion of,  270;  Roebling  floor,  284; 

setting,  269;  tie-rods 270,  274 

Footings,  centre  of  pressure  in,  26; 
computing  the  weight  on,  23;  ex- 
ample, 24;  inverted  arch  for,  67; 

proportioning 22 

Footings,  brick 65 

"         concrete,    62;     specifica- 
tions for 373 

Footings,  concrete,  with  tension  bar,    42 

masonry 02 

"         steel  beam 44 

stone 63,374 

timber 52 

Foundations:  caisson,  57;  Chicago 
practice,  91  ;  continuous,  22  ; 
depth  of,  17,  21 ;  designing  of, 
21 ;  pile,  31;  spread,  44;  superin- 
tendence of,  29,  77;  underpin- 
ning of,  88.  See  also  footings. 
Foundations  for  World's  Fair  build- 


ings. 


54 


Foundations  of  the  City  Hall,  Kan- 
sas City 55 

Foundations  of  the  Manhattan  Life 
Building,  New  York 57 

Foundations  of  the  new  Stock  Ex- 
change, Chicago 56 

Foundations  on  compressible  soils..     31 


Foundation  walls,  69;  specifications 
for,  374;  stone,  bonding,  70;  fill- 
ing of  voids,  72;  superintendence 

of,  77;  thickness  of 73 

Freestone,  see  also  sandstone 131 

Freezing  of  mortar 117 

Furring  blocks 233 

Furring  for  walls,  tile 299 

Furring  for  wire  lathing.  .321,  350,  388 


Georgia  marble 129,  392,  394 

Girder  casings,  fireproof 294 

Glazed  bricks 197 

Gneiss,  see  also  granite 125 

Granite,  characteristics  of,  124; 
chemical  composition  of,  393;  dis- 
tribution of,  125;  effect  of  heat 
on,  125,  398;  strength  of,  391, 

400;  weight  of 391 

Granite  capping  for  piles 39 

Gravel  soils 1 8 

Grillage  on  piles 40 

Grounds 324,   339 

Grout 114 

Guastavino  floor  arch 275 

H 

Hair  for  plastering 329 

Hammond  metal  furring 321 

Hard  wall  plasters,  335;  advantages 
of,  339;  application  of,  338;  ce- 
ment plasters,  336;  chemical  pias- 
ters, 337;  how  sold,  338;  specifi- 
cations for .- 387 

Hollow  tile,  260;  ceilings,  293; 
floor  arches,  263;  partitions,  297; 

roofs,  292 ;  wall  furring 299 

Hollow  walls 228,  232 

Hoop  iron  bond 217 


Imitation  marbles 343 

Inverted  arches  in  foundations,  67; 

calculations  for 68 

Iron  supports  for  lintels 164 

Iron  supports  for  mason  work,  301; 
cast  iron  arch  girders,  303;  cast 
iron  lintels,  302;  supports  for  bay 
windows,  305,311;  wall  supports 

in  skeleton  construction 307 

Ironwork:  Bearing  plates,  312; 
chimney  caps,  316;  coal  hole  rings 
and  covers,  316;  door  guards,  313; 
skewbacks 312 

J 

Joining  new  brick  walls  to  old 222 

Joints  in  ashlar 178 


4i8 


INDEX. 


Joints  in  brickwork,  thickness  of. . .  205 

Joints,  slip 180 

foist  hangers 219 


Keene's  cement 343 

Kilns  for  burning  bricks:  continu- 
ous, 197;  down-draft,  196;  up- 
draft 195 


Label  mouldings 169 

Lafarge  cement Ill 

Lathing,  318;  in  fireproof  construc- 
tion, 350,  388;  specifications  for, 

386,  388,  389 

Laths:  Bostwick  lath,  325,  389; 
Byrkit-Hall  rheathing  lath,  319; 
expanded  metal  lath,  324;  sheet 
metal  laths,  324;  wire  laths,  320, 

388;  wooden  laths 319 

Lava  stone 134 

Laying    bricks,     205 ;     in    freezing 

weather 208,  382 

Laying  out  stone  ashlar 177 

Laying  out  stonework 162 

Lee  hollow  tile  and  cable  rod  floor..  281 
Lime,    characteristics   of,   94;    how 
sold,  93;   hydraulic,   97;  impuri- 
ties  in,    93;   nature   of,   93;  pre- 
serving,  96;  slaking  and  making 

into  mortar,  94;  weight  of 114 

Lime  and  cement  mortar 114 

Lime  mortar,  -brick  dust  in,  99; 
durability  of,  96;  how  made,  94; 
proportions  of,  94;  setting  of,  96; 

white  and  colored 95 

Lime  plaster 327 

Lime  putty 96 

Limestone,  characteristics  of,  126; 
chemical  composition  of,  393;  de- 
scription of  American,  127; 
strength  of,  391,  400;  varieties 

of,  127;  weight  of 391 

Lintels,  relieving  and  supporting.  ..  164 
List  of  stone  buildings  in  the  United 

States 395 

Loam  and  made  land 19 

M 

Machine-made  mortar 330 

Manufacture  of  bricks:  by  dry  clay 
process,  194;  by  hand,  190;  by 
soft  mud  process,  191;  by  stiff 
mud  process,  192;  drying  and 

burning,  195;  repressing 193 

Manufacture  of  terra  cotta 249 

Marble,  characteristics  of,  128; 
chemical  composition  of,  394;  de- 


scription     of      American,      129; 
strength  of,  392,  400;  weight  of,  392 

Marble,  imitation   343 

Masonry,  see  stonework,  safe  work- 
ing loads  for 400 

Masonry  wells  for  foundations 55 

Measuring  brickwork 246 

plaster  work 354 

"          stonework 185 

Metal  laths,  see  also  lathing 320 

Metal   furring  for  wire   lath,  321; 

specifications  for 388 

Metropolitan  fireproof  floor 282 

Mixing  colored  mortar 123 

"       concrete 119,  365 

"      mortar  for  plastering 329 

Mortar,  cement:  proportions  and 
mixing,  112;  specifications  for, 
375,  379;  strength  of,  113,  115, 

400;  use in 

Mortar,  colored 95 

Mortar,  lime,  durability  of,  96; 
machine-made,  330;  mixing  of, 
94;  proportions  of,  94;  specifica- 
tions for 379 

Mortar,  lime  and  cement,  mixed.  .  .  114 

' '       Rosendale  and  Portland  ce- 
ment, mixed 113 

Mortar,  adhesion  of 115 

"       change  of  volume  in  setting  1 18 
"       data  for  estimating  cost  of..  115 

' '       for  brickwork 205 

for  plastering 329 

"       freezing  of 117 

"       plaster  of  Paris  in 116 

"       safe  crushing  strength  of. .  400 

"       salt  in 117 

' '       sugar  in 117 

"       to      make      impervious     to 

water 116 

Mortar   colors    and    stains:    kinds, 

use,  objections  to,  122;  mixing.  .  123 
Moulded  bricks 210 

N 

Natural  cements 99,  101,  102 

Nature  of  soils 14 

Needling  walls  and  foundations. ...     87 


Ohio  stone 133 

Onyx  marbles 130,  395 

Openings  in  walls 72,  221 

Ornamental    brickwork,    209;    cor- 
nices, 210;  surface  patterns 212 


Painting  stonework  . . , 
Partitions,  hollow  tile. 


148 
297 


INDEX. 


419 


Partitions,  thin  solid:  of  metal,  351; 

of  tile 299 

Party  \\alls,  thickness  of 225 

Pavements,  cement,  85;  stone 84 

Paving  bricks 199 

Paving,  brick,  specifications  for. . . .  382 

Peach  bottom  slate 138 

Pile  foundations,  31;  objections  to,  41 
Piles,  actual  loads  on,  38;  bearing 
power  of,  35;  classes  of,  31;  cut- 
ting off  and  capping,  39;  Engi- 
neering News  formula  for,  35; 
experiments  on,  36;  manner  of 
driving,  33,  materials  for,  32; 
municipal  regulations,  36;  point- 
ing and  ringing,  32;  spacing  of, 

38;  specifications  for 375 

Plaster:  lime,  327;  hard  wall,  335; 
machine-made,  330.  See  also 
plastering. 

Plaster  cornices 341 

Plaster  of  Paris,  340;  in  lime  mortar,  116 
Plastering,  materials  for,  327;  mix- 
ing, 329;  putting  on,   332;  speci- 
fications   for,    386;    superintend- 
ence   of,    352;     with    hard    wall 

plasters 335 

Plastering,  cost  of 355 

Plastering,    external:     rough    cast, 

344;  staff,  347;  stucco 346 

Plastering  in  fireproof  construction..  350 

Pointing  stonework 182 

Porous  hollow  tiling 260 

Portland   and    Rosendale   cements, 

mixed 113 

Portland  cement,  103;  activity  and 
weight,  106;  American,  104; 
color,  105;  firmness  and  sound- 
ness, 107;  specifications  for,  in; 
strength  of,  107,  no,  in;  testing,  105 

Pozzuolanas 98 

Preservation  of  stonework:  by  oil, 
149;  by  painting,  148;  by  Ran- 

some's  process 149 

Pressed   bricks,    201;    manufacture 

of,  194;  moulded  and  arch 202 

Proportions  of  materials:  in  con- 
crete, 120,  358,  363;  in  lime  mor- 
tar, 94;  for  plastering,  331;  in 
Portland  and  Rosendale  cement 

mortars 113 

Proportions  of  sand  and  cement  in 

mortar 113 

Protection  of  floor  arches . .  270 

"         of  stonework 148,  182 


Quantities  of  materials  required  in 
concrete,  122;  in  mortars,  114; 
in  wall  plaster 332 


Quoins  and  jambs 155 


Ransome  &  Smith  floor 279 

Relieving  and  supporting  lintels... .  164 

"         arches  and  lintels 237 

"         beams  over  arches 170 

Requisites  of  good  bricks 203 

Retaining  walls,  proportions  for.  ...     74 

Rock  foundation  beds 16 

Roebling  fireproof  floor 284 

Roman  cement 103 

Roofs,  fireproof 292 

Rough  cast  plastering 344 

Rubble  arches 173 

Rubble  work,   description  of,   150; 
measurement  of 185 


Salt  in  mortar 117,  382 

Sand  as  a  foundation  bed 18 

"    finish,  335;  specifications  for,  386 

"    for  mortar,  testing,  etc 95 

"    for  plastering  mortar 328 

Sandstones,  131;  composition  of, 
131,  393  ;  distribution  of,  132; 
properties  of,  132 ;  strength  of, 

392,  400;  weight  of 392 

Scagliola  ...'..' 343 

Screeds  in  plastering 333 

Seasoning  of  stone 148 

Segmental  floor  arches 272 

Selection  of  building  stones  .  . .  139,  145 
Setting  cut  stone,  181;  specifications 

for 377 

Setting  hollow  tile  floor  arches,  flat, 
269;  segmental,  275;  specifica- 
tions for 383 

Setting  terra  cotta,  254;  specifica- 
tions for 385 

Setting  of  cement 99,  106 

"     of  lime  mortar 96 

Shale,  blue 134 

Shoring  up  of  buildings 86 

Side-method  hollow  tile  floor  arches  263 

Sidewalk  vaults 83 

Sidewalks,    cement,     85;    concrete, 

monolithic,  368;  stone 84 

Sills,  slip 166 

"     stone,  cutting  and  setting. . .  .  166 

Size  of  bricks 202 

Skeleton     construction,    details    of 

wall  supports 307 

Skim  coat 334 

Slate,  135;  absorption,  market  qual- 
ities and  uses  of,  136;  color,  136; 
constituents  of,  135,  395;  distri- 
bution of,  136;  hardness  of,  135; 
tests  for,  135,  136;  weight  and 
strength  of 135,  393 


420 


INDEX. 


Slip  joints 180 

Slip  sills 166 

Soapstone,  nature  and  uses  of 139 

Soft  mud  bricks 191 

Soils,  actual  loads  on,  20;  bearing 
power  of,  19,  20,  borings  in,  15; 

nature  of 14 

Soils,  kinds  of:  clay,  17;  compress- 
ible, 31;  gravel,  18;  loam  and 
made  land,  19;  mud  and  silt,  19; 

rock,    16;  sand 18 

Spandrel  supports 308 

Spandrels  over  stone  arches 171 

Specifications  for  brick  paving 382 

brickwork 377 

"  concrete  footings,  373 

"  cut  stonework...  376 

' '  excavating       and 

grading 372 

Specifications  for  fireproofing 382 

granite 376 

"               lathing  and  plas- 
tering   386 

Specifications  for  laying  masonry  in 

freezing  weather 382 

Specifications  for  metal  furring. .  .  .  388 

"  mortar  for  brick- 

work, 379;  for  fireproofing,  383; 

for  stonework 375 

Specifications  for  piling 373 

Portland  cement.,  m 
Roebling  fireproof 

floors 390 

Specifications  for  setting  stonework,  377 

stonework 374 

terra   cotta    trim- 
mings   385 

Specifications  for  thin  partitions.  . .  389 

wire  lathing 388 

Spread  foundations 42 

Staff 347 

Staining  of  plastered  ceilings 270 

Stairs,  stone 176 

Staking  out  buildings 13 

Steel   beam   footings,    44;   calcula- 
tions, 47;  manner  of  using,  45;  pro- 
tection from  rust,  46 ;  under  piers,     50 
Steel  supports  for  mason  work,  see 

also  iron  supports 301 

Stiff  mud  bricks 192 

Stonecutting  and  finishing 155 

Stonecutting  tools 155 

Stone    footings,    63;    bedding,    64; 

offsets  for 64 

Stone  foundation  walls 70 

Stone  pavements. , 84 

Stone,  seasoning  of 148 

Stone,  set  on  bed 142 

Stone  steps  and  stairs 176 

Stone  trimmings 174 


Stonework:  arches,  167,  170;  ash- 
lar, 151;  cleaning  down,  183; 
defects  in,  186;  finish  of,  158; 
laying  out,  162;  measurement  of, 
185;  patching,  187;  pointing  and 
protecting,  182;  rubble,  150;  set- 
ting of,  181;  specifications  for, 
374;  superintendence  of,  186; 
trimmings,  155,  174;  working 

strength  of 400 

Stones,  building 139 

Strength  of  brick  piers,  actual 399 

"          bricks 204 

"          brickwork 244,  400 

"          concrete 121,  366,  400 

"          flat  floor  arches 274 

granites 391,  400 

"          iron 401 

"          limestones 391,  400 

"          marbles 392,  400 

"          mortars 115,  400 

"          Portland  cement. .  .  107, 

no,  in 

"          Portland    cement    mor- 
tars  113,  115 

Strength  of  Rosendale  cement 103 

"          sandstones 392,400 

"          segmental  floor  arches..  274 

slate 393 

steel 401 

"          stone  columns  and  ma- 
sonry  183 

Strength  of  stone  lintels 184 

"          terra  cotta 257 

"          timber 401 

Stucco  work,  340;  for  external  plas- 
tering, 346;  fibrous  plaster 344 

Sugar  in  mortar 117 

Superintendence  of  brickwork 247 

"  concrete  work.  . 

77,  366 

excavation 29 

"  footings      t  and 

foundation  walls 77 

Superintendence     of     lathing     and 

plastering 352 

Superintendence  of  stonework 186 

Surface  patterns  in  brick 212 

Syenite,  see  also  granite 125 


Templates,  stone 180 

Tennessee  marble 1 29 

Terra  cotta,  architectural:  color, 
250;  composition  and  manufac- 
ture, 251;  durability  of,  251;  ex- 
amples of  construction,  253;  lay- 
ing out,  251;  setting  and  point- 
ing, 254;  specifications  for,  385: 


INDEX. 


421 


use  of,  251;   weight  and  strength 

of 257 

Terra  cotta  grounds  for  cornices.  . .  351 
Testing  building  stones,  146;  by 

acid,    absorption     and    fracture, 

147;    by   compactness,    146;    by 

solution 148 

Testing  natural  cements 102 

"  Portland  cements 105 

"  soils,  for  bearing  power,  15,  20 

Thickness  of  brick  walls 222,  225 

"  foundation  walls 73 

"  joints  in  brickwork, 

205 ;  in  stonework 179 

Thin  partitions:  metal,  351;  tile, 

299;  specifications  for 389 

Tying  walls  at  angles 221 

Tie-rods  for  floor  arches 270,  274 

Timber  footings,  52;  calculations 

for 54 

Timber  foundations  for  temporary 

buildings  54 

Tools  for  stonecutting 155 

Trap  stone 134 

Trimmings,  stone:  columns,  174; 

copings,  entablatures 175 


U 


Underpinning  foundation  walls,  88; 
Chicago  practice 91 


Vault  walls 76 

Vaults,  brick 237 

"      fireproof 368 


Vaults  under  sidewalks  and  steps.. .     83 

Veneer  construction 233 

Vermont  marble 129 

W 

Wall  anchors 218 

Wall  furring,  tile 299 

Wall  supports  in  skeleton  construc- 
tion   307 

Wall  ties 215,  231,  233 

Walls:    area,    76;    foundation,    69; 
retaining,    74;    thickness  of,    73, 

222;   vault 76 

Waterproofing  cellars 401 

"  brick  and  stonework,  243 

Weight  of  bricks 202 

"         granite 391 

"         hollow  tile  floor  arches: 

flat,  267;  segmental 274 

Weight  of  lime 114 

' '         limestones 391 

marbles 392 

"         natural  cement 102 

"         onyx  marbles 395 

"         Portland  cement 106 

"        sandstones 392 

slate 393 

terra  cotta 257 

Wetting  bricks 116,  208 

White  coat 335 

Whitewashing 349 

Window  and  entrance  areas 81 

Wire  lathing,  320;  specifications  for,  388 

Withes  in  chimneys 240 

Wood  in  walls 225 

Wooden  bricks 226 


CLASSIFIED  LIST  OF  ADVERTISEMENTS. 


Cement. 

(Portland)  Atlas  Cement  Co iii 

(Lafarge)  Brand,  James vii 

(Hydraulic  and  Portland)  Cummings  Cement  Co.,  The vi 

(Dyckerhoff)  Thiele,  E iv 

Concrete  Construction. 

Aberthaw  Construction  Co vi 

Ransome  &  Smith  Co vi 

Roebling's  Sons  Co.,  John  A x 

Consulting  Architect. 

Kidder,  F.  E ; xii 

Itro  wiiNtoiin  (Hnmmelstown). 

Hummelstown  Brown  Stone  Co « iv 

Expanded  Metal  Lathing. 

Central  Expanded  Metal  Co 

Eastern  Expanded  Metal  Co 

New  York  Expanded  Metal  Co 

Northwestern  Expanded  Metal  Co 

Merritt&Co , 


Fireproof  material  and  Construction. 

Aberthaw  Construction  Co 


Central  Expanded  Metal  Co 

Eastern  Expanded  Metal  Co 

Expanded  Metal  Fireproofing  Co 

Gilbert  &  Bennett  Manufacturing  Co.,  The 

New  York  Expanded  Metal  Co 

Northwestern  Expanded  Metal  Co 

Merritt  &  Co 

Ransome  &  Smith  Co 

Roebling's  Sons  Co.,  John  A '..... 

Terra  Blanca  Fireproofing  Co vii 

Fireplace  Mantel*. 

Fiske,  Homes  &  Co xi 

Granite    Ullford  Pink). 

Ross  Granite  Co. ,  The xi 


Hard  Wall  Planters. 

(Best  Bros.  Keene's  Cement)  Fiske,  Homes  &  Co xi 

Limestone  (Bedford). 

Perry,  Matthews  &  Buskirk  Co viii 

Marble  (Georgia  White). 

Southern  Marble  Co.,  The ix 

Metal  Furring. 

Gilbert  &  Bennett  Manufacturing  Co.,  The viii 

Roofing  Slate. 

(Red)  Pritchard,  R.  B viii 

(Green)  Eureka  Slate  Quarries vii 

Wall  Ties. 

Prescott  &  Son,  J.  B x 

Wire  Lathing. 

Clinton  Wire  Cloth  Co iv 

Gilbert&  Bennett  Manufacturing  Co.,  The viii 

Roebling's  Sons  Co.,  John  A x 


An  VER  TISEMENTS. 


ATLAS 

PORTLAND  CEMENT, 


Guaranteed  to  be  equal  to  any  and 

superior  to  most  of  the 

Foreign  Brands. 


OFFICIAL  TESTS 

Nos.    3567    and    3568,    made    by   the     DEPARTMENT     OF 

DOCKS,  New  York,  March  31,  1894,  being  part  of 

contract  No.  464  for  8,000  barrels  : 

Tensile  Strength,  7  days,  neat  cement 622  Ibs. 

7  days,  2  parts  sand  to  i  of  cement. .  .322  Ibs. 
Pats  steamed  and  boiled Satisfactory. 


Used  EXCLUSIVELY  in  the 

HAVEMEYER,  ST.  PAUL,  AMERICAN  SURETY,  BANK  OF 

COMMERCE,  JOHNSTON  and  PRESBYTERIAN  BLDGS. 

And   NEW    YORK     CENTRAL    R.   R.   BRIDGE 

OVER    HARLEM   RIVER. 


ATLAS  CEMENT  COMPANY, 

143  liberty  Street  MEW  KIRK  GUY. 


iv  AD  VER  T1SEMENTS. 

DYCKERHOFF  PORTLAND  CEMENT 

Is  superior  to  any  other  Portland  Cement  made.  It  is  very  finely  ground,  always 
uniform  and  reliable,  and  of  such  extraordinary  strength  that  it  will  permit  the 
addition  of  25  per  cent,  more  sand,  etc.,  than  other  well-known  Portland  Cements, 
and  produce  the  most  durable  work.  It  is  unalterable  in  volume  and  not  liable  to 
crack. 

Pamphlet  with  directions  for  its  employment,  testimonials  and  tests  sent  on  application. 

McPHEE  &   McGINNITY,  E.  THIELE, 

Denver,  Colo.  78  William  Street,  New  York. 

Sole  Agent  United  States. 

Clinton  Wire  Cloth  Co., 

MANUFACTURERS  OF 


STIFFENED.  PLAIN.  GALVANIZED. 

CLINTON,          NEW  YORK,          BOSTON,          CHICAGO, 


ALLEN  WALTON,  President.  ALLEN  K.  WALTON,  Sec'y  and  Treas. 

ROBERT  J.  WALTON,  Superintendent. 

Contractors  for  all  kinds  of  Cut  Stonework. 

HUMMELSTOWN  BROWN  STONE  COMPANY, 

Quarrymen  and   Manufacturers   of 

Building  Stone,  Sawed  nagging  and  Tile. 

Waltonville,  Dauphin  County,  Pa. 

Telegraph  address,  Brownstone,  Pa. 


Parties  visiting  the  quarries  will  leave  cars  at  Brownstone  Station 
on  the  Philadelphia  and  Reading  Railroad. 


AD  VER  TISEMENTS. 


Expanded  fletal 

FIRE  PROOF 

CONSTRUCTION. 


No.  1  or  Golding  System. 


OUR    SYSTEMS     OF 


Concrete  and  Expanded  Metal  Flooring, 

Solid  Partitions,  Suspended  Ceilings, 

Protection  of  Columns,  Girders,  etc., 

ARE  ABSOLUTELY  FIRE  PROOF,   LIGHT  AND 

OF    GREAT    STRENGTH,    WITH 

MINIMUM  OF  IRON. 


For  Estimates  address  either  of  the  following  Associate  Companies: 
EASTERN  EXPANDED  MKTAL  CO  ,  12  Brottle  St.,  BOSTON,  MASS. 
SOUTHERN  EXPAXDKD  METAL  CO.,  Builder*'  Exrhango,  WASHINGTON.  D.  C. 
SOUTH WESTERN  EXPANDED  METAL  CO.,  860  Old  Colony  KntldinK,  CHICAGO,  ILL. 
CENTRAL  EXPANDED  MKTAL  CO.,  681  Wood  St..  PITTSBURGH,  PA. 
NEW  YORK  EXPANDED  METAL  CO..  256  Broadway,  KEW  YORK. 
EXPANDED  MKTAL  FIREPROOKIXG  CO.,  8«0  Old  Colony  Building,  CHICAGO,  ILL. 
MEIilillT  &  CO.,  1024  Iiidge  Arenae,  PHILADELPHIA,  PA. 


AD  VER  T1SEMENTS. 


and 

The  Opportunity  for  Live  Men  with   or  without  Technical   Knowledge. 


\A7LJV    \I  r^      InYest  Time'  Ener£ 

VV  11    I       IN  \J  1      Brains  Successfully? 


Building  Material. 

Ttxricf^H  Trr»ti  construction  ahead  of  all  other  systems  in 
1  WlSiea  iron  effectiveness,  universality  and  simplicity. 

(pitched,  nigged  or  tooled}.    The  resemblance  between 
these  and  natural  stone  is  perfect. 

UNSIGHTLY  CRACKS  prevented  by  shrinkage  joints,  invisible,  unobjectionable. 
CONCRETE  "WALLS  built  plumb  by  easily  handled  and  economical  molding  apparatus. 
SIDEWALK  LIGHTS-Ransome's  Monolithic—  latest,  cheapest  and  best. 

RANSOME'  S   PATENT  RIGHTS   sold   for 
States  or  Counties. 

Drawings,  Circulars  and  Complete  Information  npon  application. 


RANSOME    &    SMITH    CO., 

CONCRETE    SPECIALISTS, 
MONADNOCK    BLOCK,     CHICAGO. 

See  pages  279-280.  See  pages  357-36& 

ABERTHAW  CONSTRUCTION  CO., 

7  Exchange    Place,    Boston,    flass. 

CONTRACTORS   FOR 

Concrete    Building   Construction, 

FIREPROOF  FLOORS,  WALLS,  STAIRS,  STEPS,  LIGHTED  SIDEWALKS,  Etc.,  Etc. 

...    BY  THE    .    .    . 

RANSOME  Sc  SMITH  SYSTEM. 

Sole  Owners  of  these  Patents  for   Maine,   Massachusetts,  Rhode  Island 
and  Connecticut. 

ESTABLISHED  1854. 

URIAH  CUMMINOS,  President.  PALMER  CUMMINOS,  Treasurer  and  Gen'l  Mgr. 

HOMER  S.  CUMMINQS,  Secy,  and  Counsel.          RAT  P.  CUMMINGS,  Vice-President. 
Stamford,  Conn.  Buffalo,  N.  Y. 

THE  CUMMINGS  CEMENT  CO., 

MANUFACTURERS  OF 

HYDRAULIC  ROCK  CEMENT  AND  PORTLAND  CEMENT. 

The  only  company  in  this  country  sending  test  sheet  with  each  car  load  ship- 
ment, showing  purchaser  the  quality  of  the  cement  shipped. 

Geueral  Offices:  Elllcott  Square  Bulldiug,  Buflklo,  N.  Y. 
New  England  Office:  Stamford,  Coun.    Cement  Works  at  Akron,  N.  Y. 

THE  LARGEST  CKMKNT  WORKS  m  THE  UNITED  STATES. 


AD  VER  TISEMENTS. 


TflBDIl    RUMPS    QTAWfiQ   TUP   TPQT 

IMM  1M1M  olAWJJo  lilfi  flSSL 

UNSURPASSED  AS  A  FIREPROOF1NG. 

UNEQUALLED  AS  A  NON-CONDUCTOR. 

Applicable  to  both  Wood  and  Iron  Construction. 
Universally  approved  wherever  used. 

CONTRACTS   TAKEN  IN  ALL    PARTS    OF    THE    UNITED    STATES. 

Correspondence  solicited.      Estimates  cheerfully  furnished. 


TERRA  BLANCA  FIREPROOFING  COMPANY, 

WORKS  :  Loomis  St.  and  Northern  Pacific  Tracks. 
OFFICE  :  No.  569  Loomis  St.,  Chicago. 

Lafarge  Cement 


Perfect    Cement.) 

For  Setting,  Pointing  and  Backing,  Limestone,  Granite  and  Marble  Fronts,  Monu- 
ments, etc.  Absolutely  non-staining  and  the  finest  Portland  Cement  manufactured. 
I  'or  all  purposes  Lafarge  gives  the  best  results. 

IMPORTED   SOLELY    BY 


81  Fulton  Street,  New  York.  34  Clark  Street,  Chicago,  111. 

Eureka  Slate  Quarries, 

FAIR  HAVEN,  VERflONT. 

The  oldest  and  largest  UNFADING  GREEN  SLATE  Quarry  in 
the  United  States. 

Slates  furnished  of  any  thickness  desired,  and  also  drilled  and 
countersunk  when  so  ordered. 

Specially  selected  on  Architects'  specification  and  a  certificate  fur- 
nished. A.  TUTTLE,  Treasurer. 


viii  AD  VER  TISEMENTS. 

"6  &  B"  STEEL  WIRE  LATHING 

.    .    .   AND    ...  FOR    FIREPROOFING 


HAMMOND'S  METAL  FURRING.     SoS".  CONSTROC: 

The  two  combined  form  a  perfect  plastering  surface;  and  when  properly  covered  with 
mortar  a  permanent  fire-resisting  wall—  a.  ways  intact  and  immaculate—  is  ootainedat  a  reason- 
able cost. 

ipprored  by  Leading  Architects,  Insurance  Companies  and  Contractors. 

See  page  320,  "Metal  Laths;"  page  321,  "Hammond's  Metal  Furring;"  page,  383  "Specifications.  \ 

DESCRIPTIVE  PAMPHLET  SENT  ON  APPLICATION, 

THE  GILBERT  S(  BENNETT  MANUFACTURING  CO., 

GEORGETOWN,  CONN.        44  Cliff  St.,  NEW  YORK.        148  Lake  St.,  CHICAGO. 

EAGLE  RED  ROOFING  SLATR 

THE  BEST  RED  SLATE  IN  THE  MARKET. 

Received  Highest  Award  at  the  Columbian   Exposition  at  Chicago. 
ABSOLUTELY  UNFADING  RED  SLATE. 

Brightest  in  color  and  noted  for  evenness  and  smoothness,  which  make  the  ideal  roof. 
THEY  AKE  THE  STRONGEST  SLATE  MA  II  1C. 

Have  facilities  for  immediate  shipment  of  large  orders. 
Write  for  price  lists  and  circulars. 


RD      DBITftUADn  I 

•    Pi    rniiUnflnUf    iri 


MEW  VOICK. 


W.  N.  MATTHEWS,  Pres.  and  Gen.  Mgr.  H.  P.  PBBKT,  Secretary. 

G.  K.  PKBBT,  Vice-Pres. 


PERRY,  MATTHEWS  &  BUSKIRK  CO., 

Wholesale  Dealers  and  Q.uarrymen. 

BEDFORD  OOLITIC  LIMESTONE 

Large  Dimension  and  Mill  Blocks  a  Specialty. 

First  Quality  of  Oolitic  Stone  Guaranteed. 

Our  average  annual  shipments  aggregate  750,000  cubic  feet,  which  is  employed  in  the  erec- 
tion of  prominent  buildings  throughout  the  country.  Among  the  more  noted  of  these  are  such 
as  the  Manhattan  Life  Insurance  Building  New  York;  First  Presbyterian  Church,  Morristown, 
N.  J.;  Hoiel  Belnoir.  Boston,  Ma«s  ;  Worthinaton  Building.  Boston.  Maes.  Court  House, 
Greenfield,  Ind.  ;  Indiana  National  Bank  Building.  Indianapolis,  Ind  ;  Bank  Building,  corner 
Fourth  nnd  Pine  Streets.  St  Louis,  Mo.,  and  many  othf-rs  could  be  named 

We  are  represented  in  New  York  by  Messrs  C.  F.  Woodward  &  (Jo  ,  257  Broadway;  Phila- 
delphia by  Garrett  &  Dix,  3i01  Walnut  Street;  Boston  by  H.  Linwood  Stiles,  166  Devonchire 
Street ;  Chicago  by  W.  C.  Crosier,  815  Chicago  Stock  Exchange  Building,  corner  La  Salle 
and  Washington  Streets.  Telephone  Main  4756. 


General   Office,   BEDFORD,   IND. 


AD  VER  TISEMENTS. 


O.  W.  NORCROSS,  A.  T.  WING, 

President.  Vice-President. 


SOUTHERN  MARBLE  COMPANY, 

QUARRY  OWNERS  IND  PRODUCERS  OF 

Georgia  White  Marble 

BRILLIANT  AND  INDESTRUCTIBLE 

Quarries  at  Marble  Hill,  near  late,  Pickens  Co.,  Ga. 


Among  other  Buildings  we  refer  to 

CORCORAN  GALLERY  OF  ART,  Washington,  D,  C. 

RHODE  ISLAND  STATE  HOUSE,  Providence,  R.  I. 

STATE  MUTUAL  LIFE  ASSURANCE  BLDG,,  Worcester,  Mass. 

This  marble  is  nearly  all  Carbonate  of  Lime,  as  will  be  seen  from 
the  following  analysis  : 

Carbonate  of  calcium 98.96 

Aluminum  and  iron  oxides 22 

Insoluble  residue 61 

Loss  and  undetermined 08 

It  possesses  all  the  qualities  necessary  for  a  first-class  building 
material.  It  is  strong  and  non-absorbent,  wears  white  and  evenly, 
and  does  not  turn  gray. 

R.  P.  BEECHER,  General  Sales  Igent, 

8%  North  Forsyth  Street,  ATLANTA,  GA. 


AD  VER  TISEMENTS. 


"A  SYSTEM  OF  FIRE-PROOFING  THAT  is  FIRE-PROOF." 

The  recent  severe  fire  and  water  tests  made  by  the  New  York  Build- 
ing and  Fire  Departments  have  proved  conclusively  that 

The  Roebling  Fire-Proof  Floors 

-  ARE  - 

Absolutely  Fire-Proof. 

The  superiority  of  Concrete  over  hollow  tile  as  a  fire  and  water- 
resisting  material  has  been  established  by  practical  tests  and  fully 
confirmed  by  the  recent  fire  (May  3,  1897)  in  Pittsburgh,  Pa. 

The  Roebling  Standard  Wire  Lathing  with  the 
solid  WOVen-in  rib  is  used  exclusively  in  the  Roebling  System 
of  Fire-proofing. 

Estimates  for  Floors,  Ceilings,  Partitions,  etc.,  and  for  furring  and  applying  wire  lath- 
Ing  to  Columns  and  Girders,  and  for  Cornice  Cove  and  Ornamental  Plaster  work,  furnished 
promptly  on  application. 

Contracts  made  for  the  erection  of  all  work  of  this  character.  Send  for  illustrated  circu- 
lar on  fire-proof  construction,  fire  and  water  tests,  etc. 

See  pages  284,  285,  286,  404,  405  and  406  for  detailed  description  of  the  Roebling  System. 

JOHN  A.  ROEBLING'S  SONS  CO., 

II7-IW  Literty  St.,  Hew  York  City.  m«^^*  nr     T 

I7I-I73  Lake  St.,  Chicago,  111.  Trenton,    N.    J. 

25-27  Fremont  St.,  San  Francisco,  Cal. 

The  MORSE  WALL  TIES 

ARE    ENDORSED   BY  LEADING    ARCHITECTS 
THROUGHOUT    THE    UNITED    STATES 

HOLLOW  AND  VENEER  WALLS, 
,    TERRA  COTTA  WORK, 

As  BEING  MOST  EFFICIENT  roM  PRESSED  BR1CK 


ASHLAR,  MARBLE,  ETC. 

J.  B,  PRESCOTT  &  SON,,  Manufacturers,  WEBSTER,  MASS. 


TERRA  COTTA   FRIRZE— HXECUTEt 


AD  VER  T1SEMENTS. 


RRA   COTTA  CO. 


Estimates    I^urnishccl    foi 
ALL.  CLASSES   OF. 

BUILDING   WORK. 


THE  ROSS  GRANITE  GO,, 

ii  Foster  Street, 
WORCESTER,   MASS., 

FOR  PRICES. 


FIREPLACE   MANTELS 

OF  BRICKS  AND  TERRA  COTTA 

are  now  being  used  in  the  best   private   houses,  apartments,  club 
houses  and  office  buildings,  etc. 

SEND  FOB  OUB  COMPLETE  CATALOGUE  OF  28  NEW  DESIGNS. 

BEST     BROS.'     KEENE'S    CEMENT, 

the  most  perfect  plastering  material  on  the  market. 


FISKE,   HOMES    &   CO.,    m 


Street.  Boston.   Magg. 


AD  VER  TISEMENTS. 


F.   E.   BIDDER,   C.  E., 

CONSULTING  t  ARCHITECT 

628  FOURTEENTH  ST.,   DENVER,   (0L0. 

Calculations  made  for  Architects  and  Builders  of  all  forms  of  building  construction, 
including  iron  and  wooden  trusses,  girders,  etc.  Certificates  of  strength  and  proper 
construction  of  buildings.  Prompt  attention  given  to  consultations  by  mail. 

Terms  Reasonable,  and  Special  Prices  Given  When  Desired. 

During  fifteen  years'  practice  as  a  consulting  architect,  I  have  rendered  assistance 
to  leading  architects  and  builders  from  Maine  to  California. 


.      .      .      THE      ,      .      . 

ARCHITECTS'  •»  BUILDERS' 

POCKET  BOOK 

OP 

MENSURATION,    GEOMETRY,    GEOMETRICAL    PROBLEMS,     TRIGONOMETRICAL 
FORMULAS  AND  TABLES,  STRENGTH   AND   STABILITY   OF    FOUNDA- 
TIONS, WALLS,  BUTTRESSES,  PIERS,  ARCHES.  POSTS,  TIES, 
BEAMS,  GIRDERS,  TRUSSES,  FLOORS,  ROOFS,  ETC. 

IN  ADDITION  TO  WHICH  19 

A  GREAT  AMOUNT  OF  CONDENSED  INFORMATION: 

STATISTICS  AND  TABLES   RELATING  TO   CARPENTRY,  MASONRY,  DRAINAGE, 
PAINTING  AND  GLAZING,  PLUMBING,  PLASTERING,  ROOFING,  HEAT- 
ING AND  VENTILATION,  WEIGHTS  OF  MATERIALS,  CAPAC- 
ITY   AND    DIMENSIONS    OF    NOTED    CHURCHES, 
THEATRES,  DOMES,  TOWERS,  SPIRES,  ETC. 

WITH  A  GEE  AT  VARIETY  OF  MISCELLANEOUS  INFORMATION. 
BY 

FRANK  EUGENE  KIDDER,  C.  E., 

Consulting  Architect,  Denver,  Colo. 
Author  of  "•Building    Construction   and   Superintendence." 

Morocco  flap,  $4.00. 


Illustrated  with  over  500  Engravings,  mostly  from  Original  Designs. 

Thirteenth  Edition  Revised  and  Enlarged  to  1,000  Pages. 

INCLUDING  A  GLOSSARY  OF  TECHNICAL  TERMS— ANCIENT  AND  MODERN. 

NEW  YORK : 

JOHN    WILEY    &     SONS, 
53   EAST  TENTH   STREET, 

2U  door  wc-t  of  Hroa'lw  ay. 
l8qS. 


University  of  California 

SOUTHERN  REGIONAL  LIBRARY  FACILITY 

405  Hilgard  Avenue,  Los  Angeles,  CA  90024-1388 

Return  this  material  to  the  library 

from  which  it  was  borrowed. 


